Structure of Atom hdrusuhdhjvcshkvhvb nbb
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Aug 27, 2025
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About This Presentation
Gg
Slide Content
Ashu Ghai 11th & 12th
1. Thomson Model of Atom
- Atoms are spherical
- Positive charge is embedded over the atom completely
- Negative charge is embedded over +ve charge uniformly.
- Amount of +Ve charge is equals to 0x8 charge. (Atom is neutral)
- Mass of atom is uniform ve
- His model was compared with water melon or Christmas pudding.
1. Thomson Model of Atom
- Atoms are spherical
- Positive charge is embedded over the atom completely
- Negative charge is embedded over +ve charge uniformly.
- Amount of +Ve charge is equals to 0x8 charge. (Atom is neutral)
- Mass of atom is uniform ve
- His model was compared with water melon or Christmas pudding.
Gold foil
Source of
alpha Photographic plate
Source of
alpha Photographic plate
Ashu Ghai 11th & 12th
Ques. Describe Rutherford scattering experiment. What conclusion has he
drawn from this experiment?
Ans. In 1910, Rutherford investigated the scattering of alpha particles by thin foil of
gold and as the result of that he suggested that:
i. An atom consists of very small sized positively charged nucleus.
ii. Whole mass of atom is concentrated in the nucleus. The atom is largely empty.
iii. As the atom is neutral and the central part nucleus is positively charged so
electrons are present is equal to the nuclear positive charge.
iv. The electrons are at a distance from the nucleus and are constantly revolving
around the nucleus in closed orbits.
v. The electron must be moving with a sufficiently high velocities, so that they can
orbit the nucleus, just as the earth orbits the sum. If the earth ever stopped moving, it
would fall into the sun. The electrons revolving around the nucleus are from this
analogy, called planetary electrons. Thus, atomic model is similar to the solar system.
Ques. Describe Rutherford scattering experiment. What conclusion has he
drawn from this experiment?
Ans. In 1910, Rutherford investigated the scattering of alpha particles by thin foil of
gold and as the result of that he suggested that:
i. An atom consists of very small sized positively charged nucleus.
ii. Whole mass of atom is concentrated in the nucleus. The atom is largely empty.
iii. As the atom is neutral and the central part nucleus is positively charged so
electrons are present is equal to the nuclear positive charge.
iv. The electrons are at a distance from the nucleus and are constantly revolving
around the nucleus in closed orbits.
v. The electron must be moving with a sufficiently high velocities, so that they can
orbit the nucleus, just as the earth orbits the sum. If the earth ever stopped moving, it
would fall into the sun. The electrons revolving around the nucleus are from this
analogy, called planetary electrons. Thus, atomic model is similar to the solar system.
Ashu Ghai 11th & 12th
Ques. Give the drawbacks of Rutherford’s atomic model.
Ans. According to Rutherford’s model, electron is orbiting the nucleus
hence the direction of their velocity is constantly changing that is the
electrons are accelerating. This will cause the electrons to emit or radiate
energy and electron will have lesser and lesser energy and will get closer
and closer to the nucleus until at last it spirals into the nucleus. - An
electron moving inward along a spiral path must continuously radiate
energy. However in actual practice spectral lines of fixed wavelength are
observed. oe
Ques. Give the drawbacks of Rutherford’s atomic model.
Ans. According to Rutherford’s model, electron is orbiting the nucleus
hence the direction of their velocity is constantly changing that is the
electrons are accelerating. This will cause the electrons to emit or radiate
energy and electron will have lesser and lesser energy and will get closer
and closer to the nucleus until at last it spirals into the nucleus. - An
electron moving inward along a spiral path must continuously radiate
energy. However in actual practice spectral lines of fixed wavelength are
observed. oe
Ashu Ghai 11th & 12th
Quantum number: (Address of electron)
A set of 4 number which give the position of electrons around nucleus.
1. Principle Quantum number: (1) [ z
Non € in ash = 2n |
i sregrads shells arma nudevs E
(otlate) No ein CIM) Shh = 201Y = Jer
L Quad) su = 20) Re
n=| Kehl %
Ned Let ———— M Ged) a = 2 (BY = 19e
Ne mu) | NU cht 2 (Nr
NUN
Quantum number: (Address of electron)
A set of 4 number which give the position of electrons around nucleus.
1. Principle Quantum number: (1) [ z
Non € in ash = 2n |
i sregrads shells arma nudevs E
(otlate) No ein CIM) Shh = 201Y = Jer
L Quad) su = 20) Re
n=| Kehl %
Ned Let ———— M Ged) a = 2 (BY = 19e
Ne mu) | NU cht 2 (Nr
NUN
= Ashu Ghai 11th & 12th
2. Azimuthal Quantum number: (£) : 4 hen-l ]
It represents subshells present inside the shells.
E Nr gubshuls in ashull = Sul wa
> Kohl = | Subshe
1
S-s bell
y
o
> Lesh = 2-subshells
ES
S-subchell ie sabslelX
Lt L
0 1
= mh = 3-svbshls
aay
St a A-sules holt
a $ y
o \ =
= NA = Kssbahlls
o |
S-sobcuell. ire Ia Estado
NS
2. Azimuthal Quantum number: (£) : 4 hen-l ]
It represents subshells present inside the shells.
E Nr gubshuls in ashull = Sul wa
> Kohl = | Subshe
1
S-s bell
y
o
> Lesh = 2-subshells
ES
S-subchell ie sabslelX
Lt L
0 1
= mh = 3-svbshls
aay
St a A-sules holt
a $ y
o \ =
= NA = Kssbahlls
o |
S-sobcuell. ire Ia Estado
NS
Ashu Ghai 11th & 12th
3. Magnetic Quantum number (or ma: | (m4 41)
t represents orbitals present inside subshell.
0.5 oa — [Hol 7
(s-oxbikk\ o
© postea —= 3-osbilts [ Y] T ]
(Pai Py Pe) RHONE
LO M 1e
9) A-subshed = 5 - wchilals,
(dd de dhe: EN
B Esti — Tot
37 cc Hm
3. Magnetic Quantum number (or ma: | (m4 41)
t represents orbitals present inside subshell.
0.5 oa — [Hol 7
(s-oxbikk\ o
© postea —= 3-osbilts [ Y] T ]
(Pai Py Pe) RHONE
LO M 1e
9) A-subshed = 5 - wchilals,
(dd de dhe: EN
B Esti — Tot
37 cc Hm
Ashu Ghai 11th & 12th
4. Spin quantum number : (m,)
= rre Spin chet m
an oxbitel
Er orbit Gon «Combate 2
e
> Wa oblesz chekuwise Cm,= en
aud ollo votes, anticlockwise Me)
4. Spin quantum number : (m,)
= rre Spin chet m
an oxbitel
Er orbit Gon «Combate 2
e
> Wa oblesz chekuwise Cm,= en
aud ollo votes, anticlockwise Me)
Ashu Ghai 11th & 12th
Aufbau's Principle :
~ Electrons are filled in increasing order of
energy of each subshell.
1s 2s 2p 3s 3p As 3d ....
Na = lle le
leas” 28 35 Is
: a Ww) Mn=2507
N CQ =I Sr 24 SE en
Aufbau's Principle :
~ Electrons are filled in increasing order of
energy of each subshell.
1s 2s 2p 3s 3p As 3d ....
Na = lle le
leas” 28 35 Is
: a Ww) Mn=2507
N CQ =I Sr 24 SE en
Ashu Ghai 11th & 12th
+ Hund's Rule:
According to Hund's Rule we fill single e in each orbital, after 2 p!
that pairing of electron I Gal
one / Gg GT <a]
ee ze
Le 25 Pap? oz ut Lea
> AT
+
Note: Half filled and fully filled orbitals ale more stable than hos
incomplete. Cake
> Stall
Ne = \ne AS ap Pape qu
à Frinhlde'S Hal bre
IS x 24° a = me sh E ESE
y= bs
NN
OS feat
4 AS y
+ Hund's Rule:
According to Hund's Rule we fill single e in each orbital, after 2 p!
that pairing of electron I Gal
one / Gg GT <a]
ee ze
Le 25 Pap? oz ut Lea
> AT
+
Note: Half filled and fully filled orbitals ale more stable than hos
incomplete. Cake
> Stall
Ne = \ne AS ap Pape qu
à Frinhlde'S Hal bre
IS x 24° a = me sh E ESE
y= bs
NN
OS feat
4 AS y
Ashu Ghai 11th & 12th
F Pauli's Exclusion Principle :
Pauli's Exclusion Principle states that no two electrons in the same atom
can have identical values for all four of their quantum numbers.
Le
F Pauli's Exclusion Principle :
Pauli's Exclusion Principle states that no two electrons in the same atom
can have identical values for all four of their quantum numbers.
Le
Ashu Ghai 11th & 12th
(n +1) rule:
- The rule says that the orbital having a lower value of (n+l) is filled first.
- If (n+l) value is same then fill e- in orbital with lower value of n
4 35 and(25 + Hs Gp)
3+0 2:0 4+0 3+1
=> PZ at =
a Gb) Ss
3+1 5+0
=Q =5
(n +1) rule:
- The rule says that the orbital having a lower value of (n+l) is filled first.
- If (n+l) value is same then fill e- in orbital with lower value of n
4 35 and(25 + Hs Gp)
3+0 2:0 4+0 3+1
=> PZ at =
a Gb) Ss
3+1 5+0
=Q =5
Ashu Ghai 11th & 12th
Shapes of orbitals :
a) s-orbital : Spherical b) p-orbital : Dumbbell
shape
Shapes of orbitals :
a) s-orbital : Spherical b) p-orbital : Dumbbell
shape
Ashu Ghai 11th & 12th
c) d-orbital : Double dumbbell
c) d-orbital : Double dumbbell
Ashu Ghai 11th & 12th
# Nodes :
The region where fs probability density function reduces to zero is
called nodal surfaces or simply nodes.
à var oder ok
RAT valet)
Thuobes > hel
Angular node is also referred to as the nodal plane. Angular node refers
to a plane that passes through the nucleus.
The spherical surface region where the probability of finding an electron
is zero.(Radial node)
* The total number of nodes are given by (n-1), i.e., sum of | angular
di d(n-1- dial nodes. N
A RaQuidez os
Ile 9
=1+(n-1-1)=n-1
Quy
# Nodes :
The region where fs probability density function reduces to zero is
called nodal surfaces or simply nodes.
à var oder ok
RAT valet)
Thuobes > hel
Angular node is also referred to as the nodal plane. Angular node refers
to a plane that passes through the nucleus.
The spherical surface region where the probability of finding an electron
is zero.(Radial node)
* The total number of nodes are given by (n-1), i.e., sum of | angular
di d(n-1- dial nodes. N
A RaQuidez os
Ile 9
=1+(n-1-1)=n-1
Quy
‘Ashu Ghai 11th & 12th
(a) How many subshells are associated with n = 4 ? (b) How many electrons
will be present in the subshells having m, value of -1/2 for n = 4 ?
bus 4) nH
Sabshells = 4 (sid, F)
D Ge in Wer het = 2 (UY
A E — \6 clock
NG ack
(a) How many subshells are associated with n = 4 ? (b) How many electrons
will be present in the subshells having m, value of -1/2 for n = 4 ?
bus 4) nH
Sabshells = 4 (sid, F)
D Ge in Wer het = 2 (UY
A E — \6 clock
NG ack
Ashu Ghai 11th & 12th
What is the total number of orbitals associated with the principal quantum
number n = 3 ?
hs (03)
Subchells - 3 (Sp) 4)
Dx bilals = (Eau
{ = Y ES
What is the total number of orbitals associated with the principal quantum
number n = 3 ?
hs (03)
Subchells - 3 (Sp) 4)
Dx bilals = (Eau
{ = Y ES
Ashu Ghai 11th & 12th
Using s, p, d, f notations, describe the orbital with the following quantum
numbers
(a) n=2,1=1, (b) n=4,1=0, (c)n =5,1=3, (d)n=3,1=2
O 1=5,4>3
Sl
: =
a
by Det deo ) moda
4s 3d
Using s, p, d, f notations, describe the orbital with the following quantum
numbers
(a) n=2,1=1, (b) n=4,1=0, (c)n =5,1=3, (d)n=3,1=2
O 1=5,4>3
Sl
: =
a
by Det deo ) moda
4s 3d
ey Ashu Ghai 11th & 12th
sing s, p, d notations, describe the orbital with the following quantum
numbers.
(a) n=1, I=0; (b) n = 3; I=1 (c) n = 4; | =2; (d) n=4; 1=3
sing s, p, d notations, describe the orbital with the following quantum
numbers.
(a) n=1, I=0; (b) n = 3; I=1 (c) n = 4; | =2; (d) n=4; 1=3
Ashu Ghai 11th & 12th
How many electrons in an atom may have the following quantum numbers?
(a) n= 4, m,=-% (b) n=3,1=0 (6 00
Buy a) not, me ») 11-3,2=0
Total «= 20m" 22327 G9
Total eo = De-
Told ES AS
2
How many electrons in an atom may have the following quantum numbers?
(a) n= 4, m,=-% (b) n=3,1=0 (6 00
Buy a) not, me ») 11-3,2=0
Total «= 20m" 22327 G9
Total eo = De-
Told ES AS
2
Ashu Ghai 11th & 12th
Wave motion:-
A. Mechanical Wave : Which require medium to travel (sound wave)
2. Electromagnetic waves (EM waves) : Which do not require any
medium to travel (Radio wave).
Wate : Disturbawe which
Hg (Visible Wave ) CR ef foom
Ik À auth
Wave motion:-
A. Mechanical Wave : Which require medium to travel (sound wave)
2. Electromagnetic waves (EM waves) : Which do not require any
medium to travel (Radio wave).
Wate : Disturbawe which
Hg (Visible Wave ) CR ef foom
Ik À auth
Ashu Ghai 11th & 12th
General characteristics of a wave :
© Amblikude (A): Mu dsbleceurd
E Wendler; ka (MN: Dist. blu two cons
> Gest
OT fond CT) Ter hs Het
DLL Wave
y Frl y dida aies 4 \ve
za. Tess
Dw un: Nef waves. in
\
Im eve GQ) ARTE
Te ho waver ll
Rae
5 Lak
STagk = seco)
ada FES
AN
General characteristics of a wave :
© Amblikude (A): Mu dsbleceurd
E Wendler; ka (MN: Dist. blu two cons
> Gest
OT fond CT) Ter hs Het
DLL Wave
y Frl y dida aies 4 \ve
za. Tess
Dw un: Nef waves. in
\
Im eve GQ) ARTE
Te ho waver ll
Rae
5 Lak
STagk = seco)
ada FES
AN
Ashu Ghai 11th & 12th
Relationship between wave-length, wave number, frequency and
velocity
Aa Moo XA A E a
OAs a
ES Ÿ-
a
Ale
#6 ga Dit AX
m
Ÿ= x a)
N
E N
Relationship between wave-length, wave number, frequency and
velocity
Aa Moo XA A E a
OAs a
ES Ÿ-
a
Ale
#6 ga Dit AX
m
Ÿ= x a)
N
E N
(EM waves > Ashu Ghai 11th & 12th
ELECTROMAGNETIC RADIATION:- James Clark Maxwell proposed that light
and other form of radiant energy propagate through space in the form of
waves called electromagnetic radiations or electromagnetic waves.
- Characteristics of Electromagnetic Radiations:-
A. These consists of electric and magnetic fields that oscillate in the
direction perpendicular to each other and both are perpendicular to the
direction in which the wave is travelling.
2% The two field component have some wave length and frequency.
¿All electromagnetic wave travel with the same speed. In vacuum the
speed of all types of electromagnetic radiation is 3 X 108 m/sec.
4. This speed is called the speed of light.
5, These electromagnetic radiation do not require any medium for
propagation.
ELECTROMAGNETIC RADIATION:- James Clark Maxwell proposed that light
and other form of radiant energy propagate through space in the form of
waves called electromagnetic radiations or electromagnetic waves.
- Characteristics of Electromagnetic Radiations:-
A. These consists of electric and magnetic fields that oscillate in the
direction perpendicular to each other and both are perpendicular to the
direction in which the wave is travelling.
2% The two field component have some wave length and frequency.
¿All electromagnetic wave travel with the same speed. In vacuum the
speed of all types of electromagnetic radiation is 3 X 108 m/sec.
4. This speed is called the speed of light.
5, These electromagnetic radiation do not require any medium for
propagation.
Ashu Ghai 11th & 12th
Electic Field
À = Wavelength
Electic Field
À = Wavelength
Type
Radio
7 | Wis eve 1)
Microwave
Infra-red
(Hea
Aight (ile)
Wavelength range
>0.1m
Cu frequency)
0.1m to 1 mm
1mm to 700 nm
700 nm to 400 nm
Sultraviolet
/ X-rays
/Gamma rays
* Genie xO
Ashu Ghai 11th & 12th
400 nm to Inm
1nm to 10° nm
<10% ails Em)
Max Éequení
Radio
7 | Wis eve 1)
Microwave
Infra-red
(Hea
Aight (ile)
Wavelength range
>0.1m
Cu frequency)
0.1m to 1 mm
1mm to 700 nm
700 nm to 400 nm
Sultraviolet
/ X-rays
/Gamma rays
* Genie xO
Ashu Ghai 11th & 12th
400 nm to Inm
1nm to 10° nm
<10% ails Em)
Max Éequení
Ashu Ghai 11th & 12th
A
Planck's quantum theory : ws
All EM waves or radiations are not eorfstüht but quantized and contain
small packets of energy called quantum (quanta).
In the case of visible radiation, quanta are named as photons.
_ Energy of each photon or quantum is directly proportional to
frequency of radiation.
= fr n° wu ox Polos
© | Energy À Eu y
=) e X fou, Lune pe
=D
ca ,
Ke Planck ct
he C63x\p TS
A
Planck's quantum theory : ws
All EM waves or radiations are not eorfstüht but quantized and contain
small packets of energy called quantum (quanta).
In the case of visible radiation, quanta are named as photons.
_ Energy of each photon or quantum is directly proportional to
frequency of radiation.
= fr n° wu ox Polos
© | Energy À Eu y
=) e X fou, Lune pe
=D
ca ,
Ke Planck ct
he C63x\p TS
Ashu Ghai 11th & 12th
oe effect : Introduced by H.Hertz :
- When we expose surface of metal to EM Wave carrying some
energy which is sufficient to eject e-, photoelectric will occur.
EM Wave E E = Evony of Em wave
e W, Werk Buchen
Ra che À Ma? vg veg iced?
El bejed € Cam whe À
x E LEON
SW, >
riss
AN = ERE Atha Feequnty sequieed) foe
Pdo cac Ka = Weel E
oe effect : Introduced by H.Hertz :
- When we expose surface of metal to EM Wave carrying some
energy which is sufficient to eject e-, photoelectric will occur.
EM Wave E E = Evony of Em wave
e W, Werk Buchen
Ra che À Ma? vg veg iced?
El bejed € Cam whe À
x E LEON
SW, >
riss
AN = ERE Atha Feequnty sequieed) foe
Pdo cac Ka = Weel E
Ashu Ghai 11th & 12th
KE = nhQ-nh1. E Luchon View 4 Photo lets chal.
= ke enh Q- 2.) (0) Queda ov Photos (of hide wilt
dedos od pas ue
h jee e
© Thee is un Ie | blu allison
ad Sean 4 a
Ke
A Fu
ES ON eater] Parla | dada?
TAN
KE = nhQ-nh1. E Luchon View 4 Photo lets chal.
= ke enh Q- 2.) (0) Queda ov Photos (of hide wilt
dedos od pas ue
h jee e
© Thee is un Ie | blu allison
ad Sean 4 a
Ke
A Fu
ES ON eater] Parla | dada?
TAN
Ashu Ghai 11th & 12th
de-Broglie's Concept:
According to Dual nature, light (EM wave) shows both wave
and particle nature.
de-Broglie's Concept:
According to Dual nature, light (EM wave) shows both wave
and particle nature.
Ashu Ghai 11th & 12th
Ashu Ghai 11th & 12th
Heisenberg ‘s Uncertainty Principle:
We cannot calculate momentum and position of a microscopic body at the
same time accurately. If we do so then there is always some error in the
measurement and the product of errors (uncertainty) is always greater
h
than or equal to ar
Heisenberg ‘s Uncertainty Principle:
We cannot calculate momentum and position of a microscopic body at the
same time accurately. If we do so then there is always some error in the
measurement and the product of errors (uncertainty) is always greater
h
than or equal to ar
Ashu Ghai 11th & 12th
The mass of a particle is 9 x 10 kg. If its K.E. is 4.0 x 10° J, calculate its
wavelength.
The mass of a particle is 9 x 10 kg. If its K.E. is 4.0 x 10° J, calculate its
wavelength.
Ashu Ghai 11th & 12th
The Vividh Bharati station of All India Radio, Delhi, broadcasts on a
frequency of 1,000 kHz (kilo hertz). Calculate the wavelength of the
electromagnetic radiation emitted by transmitter. Which part of the
electromagnetic spectrum does it belong to?
The Vividh Bharati station of All India Radio, Delhi, broadcasts on a
frequency of 1,000 kHz (kilo hertz). Calculate the wavelength of the
electromagnetic radiation emitted by transmitter. Which part of the
electromagnetic spectrum does it belong to?
Ashu Ghai 11th & 12th
Calculate (a) wavenumber and (b) frequency of yellow radiation having
wavelength 5000 A.
Calculate (a) wavenumber and (b) frequency of yellow radiation having
wavelength 5000 A.
Ashu Ghai 11th & 12th
Calculate energy of one mole of photons of radiation whose frequency is
5 x10 Hz.
Calculate energy of one mole of photons of radiation whose frequency is
5 x10 Hz.
Ashu Ghai 11th & 12th
What will be the wavelength of a ball of mass 0.1 kg moving with a velocity
of 10ms ?
What will be the wavelength of a ball of mass 0.1 kg moving with a velocity
of 10ms ?
Ashu Ghai 11th & 12th
Calculate the mass of a photon with wavelength 4 A.
Calculate the mass of a photon with wavelength 4 A.
Ashu Ghai 11th & 12th
Yellow light emitted from a sodium lamp has a wavelength (A) of 500 nm.
Calculate the frequency (v) and wavenumber ( V) of the yellow light.
Yellow light emitted from a sodium lamp has a wavelength (A) of 500 nm.
Calculate the frequency (v) and wavenumber ( V) of the yellow light.
Ashu Ghai 11th & 12th
Calculate the wavelength, frequency and wavenumber of a light wave
whose period is 2.0x 10 s.
Calculate the wavelength, frequency and wavenumber of a light wave
whose period is 2.0x 10 s.
Ashu Ghai 11th & 12th
When electromagnetic radiation of wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a kinetic energy of 2 x 10 Jmol.
What is the minimum energy needed to remove an electron from sodium?
What is the maximum wavelength that will cause a photoelectron to be
emitted?
When electromagnetic radiation of wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a kinetic energy of 2 x 10 Jmol.
What is the minimum energy needed to remove an electron from sodium?
What is the maximum wavelength that will cause a photoelectron to be
emitted?
Ashu Ghai 11th & 12th
The threshold frequency for a metal is 7.0 x 10 s . Calculate the kinetic
energy of an electron emitted when radiation of frequency 1.0 x10 s hits
the metal.
The threshold frequency for a metal is 7.0 x 10 s . Calculate the kinetic
energy of an electron emitted when radiation of frequency 1.0 x10 s hits
the metal.
‘Ashu Ghai 11th & 12th
What is the maximum number of emission lines when the excited electron
of a H atom in n = 6 drops to the ground state?
What is the maximum number of emission lines when the excited electron
of a H atom in n = 6 drops to the ground state?
Ashu Ghai 11th & 12th
A microscope using suitable photons is employed to locate an electron in an
atom within a distance of 0.1 A. What is the uncertainty involved in the
measurement of its velocity?
A microscope using suitable photons is employed to locate an electron in an
atom within a distance of 0.1 A. What is the uncertainty involved in the
measurement of its velocity?
Ashu Ghai 11th & 12th
A golf ball has a mass of 40g, and a speed of 45 m/s. If the speed can be
measured within accuracy of 2%, calculate the uncertainty in the position.
A golf ball has a mass of 40g, and a speed of 45 m/s. If the speed can be
measured within accuracy of 2%, calculate the uncertainty in the position.
Ashu Ghai 11th & 12th
Electron:
The electron was discovered by JJ THOMSON when electricity passes
through gases at extremely low pressure. These experiments were known
as discharge tube experiments.
To vacuum pump
8 O anode
cathode
High voltage
Electron:
The electron was discovered by JJ THOMSON when electricity passes
through gases at extremely low pressure. These experiments were known
as discharge tube experiments.
To vacuum pump
8 O anode
cathode
High voltage
Ashu Ghai 11th & 12th
NATURE OF CATHODE RAYS:
i. When an object is placed inside the tube it forms a shadow on the wall
opposite to the cathode. The cathode rays travel in straight lines. The rays
travel from cathode towards anodes.
ii. These rays are not visible but their behavior can be observed with the
help of certain kind of material (fluorescent or phosphorescent) which glow
when hit by them. Television tube are also cathode rays tube and television
pictures results due to fluorescence on the television screen coated with
certain fluorescent or phosphorescent materials.
NATURE OF CATHODE RAYS:
i. When an object is placed inside the tube it forms a shadow on the wall
opposite to the cathode. The cathode rays travel in straight lines. The rays
travel from cathode towards anodes.
ii. These rays are not visible but their behavior can be observed with the
help of certain kind of material (fluorescent or phosphorescent) which glow
when hit by them. Television tube are also cathode rays tube and television
pictures results due to fluorescence on the television screen coated with
certain fluorescent or phosphorescent materials.
Ashu Ghai 11th & 12th
iii. Cathode rays produce mechanical effects. Eg. When a small paddle
wheel is placed between the electrodes, it rotates. This indicate that the
cathode ray consists of material particle.
iv. In absence of electrical or magnetic fields these rays travel is straight
lines. When electric and magnetic field are applied to the cathode rays in
the discharge tube, the ray are deflected thus they consists of charged
particles.
a. Effect of electric field: Particles in the cathode rays carry negative charge
so cathode ray deflected towards positive plate.
b. Effect of magnetic field: Deflection of cathode ray towards north poles in
magnetic field
iii. Cathode rays produce mechanical effects. Eg. When a small paddle
wheel is placed between the electrodes, it rotates. This indicate that the
cathode ray consists of material particle.
iv. In absence of electrical or magnetic fields these rays travel is straight
lines. When electric and magnetic field are applied to the cathode rays in
the discharge tube, the ray are deflected thus they consists of charged
particles.
a. Effect of electric field: Particles in the cathode rays carry negative charge
so cathode ray deflected towards positive plate.
b. Effect of magnetic field: Deflection of cathode ray towards north poles in
magnetic field
Ashu Ghai 11th & 12th
- Charge and mass of electrons :
The e/m ratio is 1.7588 X 10" Ckg +
- R.A. Millikan — Oil drop experiment :
Charge on e = - 1.6 x 10°C
As, = 1.76 X 1011
m
1.6 X 10-19
= 1.76 X 10%
m = 9.1 x 107?* Kg
- Charge and mass of electrons :
The e/m ratio is 1.7588 X 10" Ckg +
- R.A. Millikan — Oil drop experiment :
Charge on e = - 1.6 x 10°C
As, = 1.76 X 1011
m
1.6 X 10-19
= 1.76 X 10%
m = 9.1 x 107?* Kg
Ashu Ghai 11th & 12th
PROTON:
E.Goldstein discovered Anode rays. These rays travelled in opposite
direction to the cathode rays. These rays are also deflected by the magnetic
and electric field. These rays were attracted towards the negative plate in
the electric field. This means that these rays consist of positively charged
particles and were also named positive ray or anode rays.
To vacuum pus
High voltage
PROTON:
E.Goldstein discovered Anode rays. These rays travelled in opposite
direction to the cathode rays. These rays are also deflected by the magnetic
and electric field. These rays were attracted towards the negative plate in
the electric field. This means that these rays consist of positively charged
particles and were also named positive ray or anode rays.
To vacuum pus
High voltage
Ashu Ghai 11th & 12th
Characteristics of Anode Rays:
1. The anode rays travel in straight lines and cast shadow of the object
placed in their path.
2. The anode rays are deflected by the magnetic and electric field like
cathode rays. But the deflection of anode ray is in the opposite direction to
that of the cathode rays.
3. Like cathode rays these rays also rotate the wheel placed in their path
and also have heating effect.
Characteristics of Anode Rays:
1. The anode rays travel in straight lines and cast shadow of the object
placed in their path.
2. The anode rays are deflected by the magnetic and electric field like
cathode rays. But the deflection of anode ray is in the opposite direction to
that of the cathode rays.
3. Like cathode rays these rays also rotate the wheel placed in their path
and also have heating effect.
Ashu Ghai 11th & 12th
4. The charge of mass ratio (e/m) for these rays is smaller than electrons.
5. Unlike cathode rays, the e/m ratio of positive rays depends upon the
nature of the gas taken in the tube
4. The charge of mass ratio (e/m) for these rays is smaller than electrons.
5. Unlike cathode rays, the e/m ratio of positive rays depends upon the
nature of the gas taken in the tube
Ashu Ghai 11th & 12th
Charge and Mass of particle consisting Anode Rays.
- The e/m ratio is 9.58 X 10 Ckg * .
. It charge has been found to be 1.622 X 10 coulomb which is equal in
magnitude but opposite in sign to that of an electron.
- Its mass can be calculated from the value of e and e/m as:
Charge and Mass of particle consisting Anode Rays.
- The e/m ratio is 9.58 X 10 Ckg * .
. It charge has been found to be 1.622 X 10 coulomb which is equal in
magnitude but opposite in sign to that of an electron.
- Its mass can be calculated from the value of e and e/m as:
Ashu Ghai 11th & 12th
Bohr’s model of atom.
The basic postulates of Bohr’s theory are:-
1. An atom consists of small heavy positively charged nucleus in the
centre surrounded by electrons. The electrons in an atom revolve around
the nucleus only in certain selected path which have a fixed value of
radius and energy. These path are called orbits. These orbits are
associated with definite energies are called energy shells or energy
levels. These are numbered as 1, 2, 3, 4 etc or K, L, M, N
Bohr’s model of atom.
The basic postulates of Bohr’s theory are:-
1. An atom consists of small heavy positively charged nucleus in the
centre surrounded by electrons. The electrons in an atom revolve around
the nucleus only in certain selected path which have a fixed value of
radius and energy. These path are called orbits. These orbits are
associated with definite energies are called energy shells or energy
levels. These are numbered as 1, 2, 3, 4 etc or K, L, M, N
Ashu Ghai 11th & 12th
2. The energy of an electron in the orbit does not change with time. In
other words as long as the electrons remain in particular orbit, it does not
lose or gain energy. This means that the energy of the electron in a
particular energy shell remains constant. Therefore these orbits are also
called stationary states or energy states. The term stationary does not
mean that electron is stationary but it means that the energy of the
electron does not change with time. This accounts for the stability of an
atom.
2. The energy of an electron in the orbit does not change with time. In
other words as long as the electrons remain in particular orbit, it does not
lose or gain energy. This means that the energy of the electron in a
particular energy shell remains constant. Therefore these orbits are also
called stationary states or energy states. The term stationary does not
mean that electron is stationary but it means that the energy of the
electron does not change with time. This accounts for the stability of an
atom.
Ashu Ghai 11th & 12th
Ashu Ghai 11th & 12th
4. The energy is emitted or absorbed only when the electrons jump from
one energy level to another. When energy is supplied to an atom its
electrons absorb one or more quantum of energy and jump to higher
energy level. This higher state of energy is called excited state. For eg.
When the electrons absorb energy equal to E,- E, it jumps to higher energy
level. When electrons jumps back to the lower energy levels, it radiates the
some amount of energy. This amount of energy emitted or absorbed is
given by the difference of the energies of the two energy levels concerned.
That is
4. The energy is emitted or absorbed only when the electrons jump from
one energy level to another. When energy is supplied to an atom its
electrons absorb one or more quantum of energy and jump to higher
energy level. This higher state of energy is called excited state. For eg.
When the electrons absorb energy equal to E,- E, it jumps to higher energy
level. When electrons jumps back to the lower energy levels, it radiates the
some amount of energy. This amount of energy emitted or absorbed is
given by the difference of the energies of the two energy levels concerned.
That is
Ashu Ghai 11th & 12th
GROUND STATE:-
When the electron is present as close to the nucleus as possible, the atom
has the minimum possible energy and is said to be in the ground state.
- If the electrons comes back from energy level having energy E, to energy
level having energy level E then the difference (E,- E) may be expressed
in term of energy E then the difference (E,— E) may be expressed in term
of energy of photon
u) 2.18x10" J| 2
2
1 Un
i
GROUND STATE:-
When the electron is present as close to the nucleus as possible, the atom
has the minimum possible energy and is said to be in the ground state.
- If the electrons comes back from energy level having energy E, to energy
level having energy level E then the difference (E,- E) may be expressed
in term of energy E then the difference (E,— E) may be expressed in term
of energy of photon
u) 2.18x10" J| 2
2
1 Un
i
Ashu Ghai 11th & 12th
Ashu Ghai 11th & 12th
Explanation of line spectrum of hydrogen:-
- When electron jumps from a lower orbit to a higher orbit, it absorbs
energy. When the electron jumps from higher orbit to lower orbit, it emits
energy.
- The amount of energy absorbed or emitted when an electron jumps from
orbit n,(initial orbit) to orbit n,(final orbit) may be given as
Explanation of line spectrum of hydrogen:-
- When electron jumps from a lower orbit to a higher orbit, it absorbs
energy. When the electron jumps from higher orbit to lower orbit, it emits
energy.
- The amount of energy absorbed or emitted when an electron jumps from
orbit n,(initial orbit) to orbit n,(final orbit) may be given as
Ashu Ghai 11th & 12th
EMISSION SPECTRUM OF HYDROGEN ATOM:
- The spectrum of hydrogen atom can be obtained by passing an electric discharge
the gas taken in the discharge tube under low pressure. The emitted light is analysed
with the help of spectroscope. The spectrum consists of a large number of lines
appearing in different regions of wave length. Some of the lines are present in the
visible region while other in ultraviolet and infra-red regions.
- Hydrogen spectra lines the general expression was found as:-
1
7 = 109,677 | —-
Y
- The expression is found to be valid for all the lines in the hydrogen spectrum and is
also known as Rydberg equation.
- Different spectral lines in the spectrum of hydrogen atom.
EMISSION SPECTRUM OF HYDROGEN ATOM:
- The spectrum of hydrogen atom can be obtained by passing an electric discharge
the gas taken in the discharge tube under low pressure. The emitted light is analysed
with the help of spectroscope. The spectrum consists of a large number of lines
appearing in different regions of wave length. Some of the lines are present in the
visible region while other in ultraviolet and infra-red regions.
- Hydrogen spectra lines the general expression was found as:-
1
7 = 109,677 | —-
Y
- The expression is found to be valid for all the lines in the hydrogen spectrum and is
also known as Rydberg equation.
- Different spectral lines in the spectrum of hydrogen atom.
Ashu Ghai 11th & 12th
Shortest and longest Wavelength
- Shortest wavelength , maximum energy
- Longest wavelength , minimum energy
Shortest and longest Wavelength
- Shortest wavelength , maximum energy
- Longest wavelength , minimum energy
[on | on | Spectral Region
Lyman .... | Ultraviolet
Balmer se ||| “Visible
Paschen À Infrared
Brackett ss.» | Infrared
Pfund .... | Infrared
Lyman .... | Ultraviolet
Balmer se ||| “Visible
Paschen À Infrared
Brackett ss.» | Infrared
Pfund .... | Infrared
Ashu Ghai 11th & 12th
BOHR’S RADIUS:-
BOHR’S RADIUS:-
Ashu Ghai 11th & 12th
LIMITATION OF BOHR’S ATOMIC THEORY:-
1. Bohr’s theory of atomic structure was quite successful in explaining the
stability of atom and the line spectrum of hydrogen atom. However some of
the limitation of Bohr’s model are:-
1. Bohr’s model of an atom could not account for the finer details of the
hydrogen spectrum absorbed using sophisticated spectroscopic techniques.
2. Bohr’s model of an atom could not explain the line spectra of atoms
containing more than one electron called multi electron atoms.
3. Bohr’s theory failed to account for the effect of magnetic field on the
spectra of atoms or ions, When the atom emitting radiation is placed in a
strong magnetic field, each spectral line is further split into a number of
lines.
LIMITATION OF BOHR’S ATOMIC THEORY:-
1. Bohr’s theory of atomic structure was quite successful in explaining the
stability of atom and the line spectrum of hydrogen atom. However some of
the limitation of Bohr’s model are:-
1. Bohr’s model of an atom could not account for the finer details of the
hydrogen spectrum absorbed using sophisticated spectroscopic techniques.
2. Bohr’s model of an atom could not explain the line spectra of atoms
containing more than one electron called multi electron atoms.
3. Bohr’s theory failed to account for the effect of magnetic field on the
spectra of atoms or ions, When the atom emitting radiation is placed in a
strong magnetic field, each spectral line is further split into a number of
lines.
Ashu Ghai 11th & 12th
4. Bohr’s theory could not explain the effect of electric field (known as
stark effect) on the spectra of atoms.
5. Bohr's theory does not provide any clue to explain the shape of
molecules arising out of the directional bonding between atoms.
6. The main objection of the Bohr's theory came from new principle
namely dual nature of matter and uncertainly principle. They introduce
the idea of wave character of electron in addition to its particle.
Characters are pointed out that the path of the motion of the electron
cannot be well defined
4. Bohr’s theory could not explain the effect of electric field (known as
stark effect) on the spectra of atoms.
5. Bohr's theory does not provide any clue to explain the shape of
molecules arising out of the directional bonding between atoms.
6. The main objection of the Bohr's theory came from new principle
namely dual nature of matter and uncertainly principle. They introduce
the idea of wave character of electron in addition to its particle.
Characters are pointed out that the path of the motion of the electron
cannot be well defined
Ashu Ghai 11th & 12th
- Zeeman effect :
Decomposition of EM waves in presence of magnetic field.
- Stark effect:
Decomposition of EM waves in presence of electric field.
- Zeeman effect :
Decomposition of EM waves in presence of magnetic field.
- Stark effect:
Decomposition of EM waves in presence of electric field.
Ashu Ghai 11th & 12th
Atomic number and mass number
- Atomic number (Z) = number of proton in the nucleus of an atom =
number of electrons in a neutral atom.
- Mass number (A) = number of protons (z) + number of neutrons (n)
Atomic number and mass number
- Atomic number (Z) = number of proton in the nucleus of an atom =
number of electrons in a neutral atom.
- Mass number (A) = number of protons (z) + number of neutrons (n)
Ashu Ghai 11th & 12th
ISOTOPES, ISOBARS & ISOTONES:-
Isotopes - Atoms of the same element which have the same atomic number
but different mass number.
Eg. Hydrogen has three isotopes.
Hydrogen (H)z=1,A=1
Deuterium (D) z = 1,A=2
Tritium (T) z = 1, A =3
ISOTOPES, ISOBARS & ISOTONES:-
Isotopes - Atoms of the same element which have the same atomic number
but different mass number.
Eg. Hydrogen has three isotopes.
Hydrogen (H)z=1,A=1
Deuterium (D) z = 1,A=2
Tritium (T) z = 1, A =3
Ashu Ghai 11th & 12th
Isobars: Atoms of different elements having the same mass number but
different atomic numbers are called isobars.
Isobars: Atoms of different elements having the same mass number but
different atomic numbers are called isobars.
Ashu Ghai 11th & 12th
ISOTONES: Atoms having same number of neutron but different mass
number are called isotones.
ISOTONES: Atoms having same number of neutron but different mass
number are called isotones.
Ashu Ghai 11th & 12th
The number of electrons, protons and neutrons in a species are equal to 18,
16 and 16 respectively. Assign the proper symbol to the species.
The number of electrons, protons and neutrons in a species are equal to 18,
16 and 16 respectively. Assign the proper symbol to the species.
Ashu Ghai 11th & 12th
What are the frequency and wavelength of a photon emitted during a
transition from n = 5 state to the n = 2 state in the hydrogen atom?
What are the frequency and wavelength of a photon emitted during a
transition from n = 5 state to the n = 2 state in the hydrogen atom?
Ashu Ghai 11th & 12th
How many neutrons and protons are there in the following nuclei ?
13. 169 24 5675, 88
66, 80, 12Mg, 26F e, 3357
How many neutrons and protons are there in the following nuclei ?
13. 169 24 5675, 88
66, 80, 12Mg, 26F e, 3357
‘Ashu Ghai 11th & 12th
Calculate the energy associated with the first orbit of He. What is the
radius of this orbit?
Calculate the energy associated with the first orbit of He. What is the
radius of this orbit?
Ashu Ghai 11th & 12th
An element with mass number 81 contains 31.7% more neutrons as
compared to protons. Assign the atomic symbol.
An element with mass number 81 contains 31.7% more neutrons as
compared to protons. Assign the atomic symbol.
Ashu Ghai 11th & 12th
An ion with mass number 37 possesses one unit of negative charge. If the
ion contains 11.1% more neutrons than the electrons, find the symbol of
the ion.
An ion with mass number 37 possesses one unit of negative charge. If the
ion contains 11.1% more neutrons than the electrons, find the symbol of
the ion.
Ashu Ghai 11th & 12th
Ashu Ghai 11th & 12th
[de-Broglie's Concept: |
According to Dual nature, light (EM wave) shows both wave
and particle nature.
R = me”
Acc-b Wave nature:
Acc. h Parhele Nature: h = MEC
o à
DER TEN EHEN A
ESE IN
. IS > dos er
[de-Broglie's Concept: |
According to Dual nature, light (EM wave) shows both wave
and particle nature.
R = me”
Acc-b Wave nature:
Acc. h Parhele Nature: h = MEC
o à
DER TEN EHEN A
ESE IN
. IS > dos er
h Ashu Ghai 11th & 12th
hs, Is h e
= Im KE
eal AVE Eng
Clarqe
hiso, KE- ¿mw
KE - LAN
2 m
Ke=1 =
ey
hs, Is h e
= Im KE
eal AVE Eng
Clarqe
hiso, KE- ¿mw
KE - LAN
2 m
Ke=1 =
ey
Ashu Ghai 11th & 12th
Heisenberg ‘s Uncertainty Principle: | (HUP )
We cannot calculate momentum and position of a microscopic body at the
same time accurately. If we do so then there is always some error in the
measurement and the product of errors (uncertainty) is always greater
h
than or equal to ar
Apte > A
Heisenberg ‘s Uncertainty Principle: | (HUP )
We cannot calculate momentum and position of a microscopic body at the
same time accurately. If we do so then there is always some error in the
measurement and the product of errors (uncertainty) is always greater
h
than or equal to ar
Apte > A
Ashu Ghai 11th & 12th
The mass of a particle is 9 x 10 kg. If its K.E. is 4.0 x 10° J, calculate its
wavelength.
Ne 663 xl”
Ans 29 xlo
. -18
a D xGxlo
KE-Ux16*53
N 663 la
lung
Az TREX o va
De fea?
Ka y
The mass of a particle is 9 x 10 kg. If its K.E. is 4.0 x 10° J, calculate its
wavelength.
Ne 663 xl”
Ans 29 xlo
. -18
a D xGxlo
KE-Ux16*53
N 663 la
lung
Az TREX o va
De fea?
Ka y
Ashu Ghai 11th & 12th
The Vividh Bharati station of All India Radio, Delhi, broadcasts on a
frequency of 1,000 kHz (kilo hertz). Calculate the wavelength of the
electromagnetic radiation emitted by transmitter. Which part of the
electromagnetic spectrum does it belong to?
ha =, = (von KH N x il?
Ne INH EE
à ne 3xlo m
eG
SS Re
(15318
The Vividh Bharati station of All India Radio, Delhi, broadcasts on a
frequency of 1,000 kHz (kilo hertz). Calculate the wavelength of the
electromagnetic radiation emitted by transmitter. Which part of the
electromagnetic spectrum does it belong to?
ha =, = (von KH N x il?
Ne INH EE
à ne 3xlo m
eG
SS Re
(15318
Ashu Ghai 11th & 12th
Calculate energy of one mole of photons of radiation whose frequency is
5 x10 Hz.
Ba the Iml 26:02. X10” plebous
Ne Sant
=(602 xin”) x6 EX TL SAT
= 602 £6 63xS xl
: Y
Calculate energy of one mole of photons of radiation whose frequency is
5 x10 Hz.
Ba the Iml 26:02. X10” plebous
Ne Sant
=(602 xin”) x6 EX TL SAT
= 602 £6 63xS xl
: Y
Ashu Ghai 11th & 12th
What will be the wavelength of a ball of mass 0.1 kg moving with a velocity
of 10ms ?
Aus M- as
T= loms”*
en
UNS
= &63xl55"
OL ALD
What will be the wavelength of a ball of mass 0.1 kg moving with a velocity
of 10ms ?
Aus M- as
T= loms”*
en
UNS
= &63xl55"
OL ALD
Ashu Ghai 11th & 12th
Yellow light emitted from a sodium lamp has a wavelength (A) of 500 nm.
Calculate the frequency (v) and wavenumber ( V) of the yellow light.
he tee À
Az Gok N° ee ES
ET : one
I 2 au)
Da a
Yellow light emitted from a sodium lamp has a wavelength (A) of 500 nm.
Calculate the frequency (v) and wavenumber ( V) of the yellow light.
he tee À
Az Gok N° ee ES
ET : one
I 2 au)
Da a
Ashu Ghai 11th & 12th
When electromagnetic radiation of wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a kinetic energy of 2 x 10J mol .
What is the minimum energy needed to remove an electron from sodium?
What is the maximum wavelength that will cause a photoelectron to be
emitted?
E E-w.tte We ahs
Au Nedoonm = ET A À
= N=E-KE
KE=2xhoy 2 Xl0?= Cox x 63x15
= UN 2 x10? a :
X 3X1?
N= Imle = 6.02 x - — DO rep
N
Ex HC 2 à
t 2° = GONE x 6-68 x 15 34 A La \ ES
By! NN
= UST
When electromagnetic radiation of wavelength 300 nm falls on the surface
of sodium, electrons are emitted with a kinetic energy of 2 x 10J mol .
What is the minimum energy needed to remove an electron from sodium?
What is the maximum wavelength that will cause a photoelectron to be
emitted?
E E-w.tte We ahs
Au Nedoonm = ET A À
= N=E-KE
KE=2xhoy 2 Xl0?= Cox x 63x15
= UN 2 x10? a :
X 3X1?
N= Imle = 6.02 x - — DO rep
N
Ex HC 2 à
t 2° = GONE x 6-68 x 15 34 A La \ ES
By! NN
= UST
Ashu Ghai 11th & 12th
The threshold frequency for a metal is 7.0 x 10 s . Calculate the kinetic
energy of an electron emitted when radiation of frequency 1.0 x10 s hits
the metal.
Pes A Tale"
a Vato! Hy
= lo xls" Hy
he ON
KE MTS UNN \oyly 127 Run)
“64 xaxly y
The threshold frequency for a metal is 7.0 x 10 s . Calculate the kinetic
energy of an electron emitted when radiation of frequency 1.0 x10 s hits
the metal.
Pes A Tale"
a Vato! Hy
= lo xls" Hy
he ON
KE MTS UNN \oyly 127 Run)
“64 xaxly y
#
Ashu Ghai 11th & 12th
A microscope using suitable photons is employed to locate an electron in an
atom within a distance of 0.1 A. What is the uncertainty involved in the
measurement of its velocity?
Aw Aw = + 0-14 ne ee
WSU X41
AY. An > ly
Him
A DIEBA "N
ARMAR Ly
Ashu Ghai 11th & 12th
A microscope using suitable photons is employed to locate an electron in an
atom within a distance of 0.1 A. What is the uncertainty involved in the
measurement of its velocity?
Aw Aw = + 0-14 ne ee
WSU X41
AY. An > ly
Him
A DIEBA "N
ARMAR Ly
Ashu Ghai 11th & 12th
A golf ball has a mass of 40g, and a speed of 45 m/s. If the speed can be
measured within accuracy of 2%, calculate the uncertainty in the position.
mzHYos = 0-04 ka Ax-Av > cia.
ts Ô d Um
= Höms-! bx 731663xly 51
Ae = 45% 2 Ux3.1H4 x d 04 X0 4
Too
(Nr. Sa.
A golf ball has a mass of 40g, and a speed of 45 m/s. If the speed can be
measured within accuracy of 2%, calculate the uncertainty in the position.
mzHYos = 0-04 ka Ax-Av > cia.
ts Ô d Um
= Höms-! bx 731663xly 51
Ae = 45% 2 Ux3.1H4 x d 04 X0 4
Too
(Nr. Sa.
The electron was discovered by JJ THOMSON when electricity passes
through gases at extremely low pressure. These experiments were known
as discharge tube experiments.
cathode ©) anode
High voltage
through gases at extremely low pressure. These experiments were known
as discharge tube experiments.
cathode ©) anode
High voltage
Ashu Ghai 11th & 12th
NATURE OF CATHODE RAYS:
_i-When an object is placed inside the tube it forms a shadow on the wall
opposite to the cathode. The cathode rays travel in straight lines. The rays
travel from cathode towards anodes.
ik These rays are not visible but their behavior can be observed with the
help of certain kind of material (fluorescent or phosphorescent) which glow
when hit by them. Television tube are also cathode rays tube and television
pictures results due to fluorescence on the television screen coated with
certain fluorescent or phosphorescent materials.
NATURE OF CATHODE RAYS:
_i-When an object is placed inside the tube it forms a shadow on the wall
opposite to the cathode. The cathode rays travel in straight lines. The rays
travel from cathode towards anodes.
ik These rays are not visible but their behavior can be observed with the
help of certain kind of material (fluorescent or phosphorescent) which glow
when hit by them. Television tube are also cathode rays tube and television
pictures results due to fluorescence on the television screen coated with
certain fluorescent or phosphorescent materials.
Ashu Ghai 11th & 12th
_ii Cathode rays produce mechanical effects. Eg. When a small paddle
wheel is placed between the electrodes, it rotates. This indicate that the
cathode ray consists of material particle.
iv. In absence of electrical or magnetic fields these rays travel is straight
lines. When electric and magnetic field are applied to the cathode rays in
the discharge tube, the ray are deflected thus they consists of charged
particles.
a, Æffect of electric field: Particles in the cathode rays carry negative charge
so cathode ray deflected towards positive plate.
b, Effect of magnetic field: Deflection of cathode ray towards north poles in
magnetic field
_ii Cathode rays produce mechanical effects. Eg. When a small paddle
wheel is placed between the electrodes, it rotates. This indicate that the
cathode ray consists of material particle.
iv. In absence of electrical or magnetic fields these rays travel is straight
lines. When electric and magnetic field are applied to the cathode rays in
the discharge tube, the ray are deflected thus they consists of charged
particles.
a, Æffect of electric field: Particles in the cathode rays carry negative charge
so cathode ray deflected towards positive plate.
b, Effect of magnetic field: Deflection of cathode ray towards north poles in
magnetic field
Ashu Ghai 11th & 12th
- Charge and mass of electrons :
Thefe/m)ratio is 1.7588 X 10" Ckg +
- R.A. Millikan — Oil drop experiment :
Charge on e” = - 1.6 x 101? C
As, = 1.76 X 1011
m
1.6 X 10-19
= 1.76 X 10%
m = 9.1 x 107?* Kg A
- Charge and mass of electrons :
Thefe/m)ratio is 1.7588 X 10" Ckg +
- R.A. Millikan — Oil drop experiment :
Charge on e” = - 1.6 x 101? C
As, = 1.76 X 1011
m
1.6 X 10-19
= 1.76 X 10%
m = 9.1 x 107?* Kg A
Ashu Ghai 11th & 12th
PROTON: Cop
E.Goldstein discovered Anode rays. These rays travelled in opposite
direction to the cathode rays. These rays are also deflected by the magnetic
and electric field. These rays were attracted towards the negative plate in
the electric field. This means that these rays consist of positively charged
particles and were also named positive ray or anode rays.
To vacuum pump
Fluorescent
ng
cathode Of
anode O)
U
High voltage
PROTON: Cop
E.Goldstein discovered Anode rays. These rays travelled in opposite
direction to the cathode rays. These rays are also deflected by the magnetic
and electric field. These rays were attracted towards the negative plate in
the electric field. This means that these rays consist of positively charged
particles and were also named positive ray or anode rays.
To vacuum pump
Fluorescent
ng
cathode Of
anode O)
U
High voltage
Ashu Ghai 11th & 12th
Characteristics of Anode Rays:
1. The anode rays travel in straight lines and cast shadow of the object
placed in their path.
2. The anode rays are deflected by the magnetic and electric field like
cathode rays. But the deflection of anode ray is in the opposite direction to
that of the cathode rays.
3. Like cathode rays these rays also rotate the wheel placed in their path
and also have heating effect.
Characteristics of Anode Rays:
1. The anode rays travel in straight lines and cast shadow of the object
placed in their path.
2. The anode rays are deflected by the magnetic and electric field like
cathode rays. But the deflection of anode ray is in the opposite direction to
that of the cathode rays.
3. Like cathode rays these rays also rotate the wheel placed in their path
and also have heating effect.
Ashu Ghai 11th & 12th
4. The charge of mass ratio (e/m) for these rays is smaller than electrons.
5. Unlike cathode rays, the e/m ratio of positive rays depends upon the
nature of the gas taken in the tube
4. The charge of mass ratio (e/m) for these rays is smaller than electrons.
5. Unlike cathode rays, the e/m ratio of positive rays depends upon the
nature of the gas taken in the tube
Ashu Ghai 11th & 12th
Charge and Mass of particle consisting Anode Rays.
- The e/m ratio is 9.58 X 10 Ckg * .
. It charge has been found to be 1.622 X 10 coulomb which is equal in
magnitude but opposite in sign to that of an electron.
- Its mass can be calculated from the value of e and e/m as:
Charge and Mass of particle consisting Anode Rays.
- The e/m ratio is 9.58 X 10 Ckg * .
. It charge has been found to be 1.622 X 10 coulomb which is equal in
magnitude but opposite in sign to that of an electron.
- Its mass can be calculated from the value of e and e/m as:
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