unit and measurement all of us have read

make sure to ask more about it.

1. ➢Jenish Magar
➢11 (B5)
PRESENTATION ON:
UNIT
AND
MEASUREMENT
•INTRODUCTION
➢Measurement of any physical quantity involves comparison with
a certain basic, arbitrarily chosen, internationally accepted
reference standard called unit. The result of a measurement of a
physical quantity is expressed by a number accompony by a unit.

2. ❖MEASUREMENT
➢The process of measuring unknown quantity with known
quantity is known an measurement.
❖UNIT
➢The quantity used as a standard of measurement is known as
unit.

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PHYSICAL QUANTITIES
➢All the quantities in terms of which laws of physics are
discribed,and whose measurement is necessary are called
physical quantities.
➢Distance/Length
➢Time
➢Mass
➢Speed
➢Velocity
➢Force
➢Acceleration
➢Power
➢Pressure
➢Work
➢Energy
➢Momentum
➢Temperature
➢Electric current

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PHYSICAL QUANTITIES
❖FUNDFAMENTAL
QUANTITIES
•Those physical quantities which are
are independent with each other.
❖DERIVED QUANTITIES
•Those physical quantities which are
derived from fundamental
quantities.
•Length, mass, time,
temperature,etc.
•Speed, velocity, acceleration,
force, momentum, power,etc.

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PHYSICAL UNIT
❖FUNDAMENTAL UNITS
•Those units which are
independent with each other.
•Length=cm
•Mass=g
•Time=sec
❖DERIVED UNITS
•Those units which are derived
from other units.
•Speed= m/s
•Velocity=m/s
•Force=kg m/s

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❖SYSTEM OF UNITS
Is the complete set of units, both fundamental and derived,
for all kinds of physical quantities.
•CGS System: In this system of units length is measured in meter,
mass in kg and time in sec.
•MKS System: In this system of units length is measured in meter,
mass in kg and time in sec.

7. •FPS System: In this system length is measured in foot, mass in
pound and time in sec.
•SI System: In this system there are 7- fundamental quantities and 2-
supplementory quantities.
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Fundamental
Quantity UNITS SYMBOL
• Mass
Kilogram kg
• Length Meter m
• Time Second sec
• Current Amphere A
• Temperature Kelvin k
• Amount of Substance Mole mol
•Luminous intensity Candela cd
Supplememtary quantity UNITS SYMBOL
• Plane angle Radian rad
•Solid angle Steratian sr

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❖DIMENSION : The dimension of a physical
quantity is defined as the power to which
fundamental quantities are raised to express
the physical quantity. Dimension of mass,
length and time are represented by
❖ DIMENSION FORMULA : The expression of the
physical quantity in terms of it's basic unit with proper
dimensions.

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