CLASS 10 OHM'S LAW.pptx

CLASS 10 CHAPTER 12 OHM'S LAW

1. CLASS – XTH TOPIC – Ohm’s Law Name:- Sandeep Jaiswal 11813483 Integrated B.Sc. B.Ed.

2. OHM’s Law Factors Affecting Resistance Combination of Resistors(Series & Parallel) Heating Effect of Electricity and its apps.

3. At constant temperature , Current flowing through a conductor is directly proportional to potential difference across its ends V𝖺I V/I = Constant = R V=IR R -> Ressiatance( Ω or ohm )

4. Fixed resistors have only one resistance value Variable resistors can be adjusted to change the resistance, example- Rheostat Fixed Resistors Rheost a t

5. Length of Conductor ->> R𝖺l Cross-sectional Area of conductor ->> R 𝖺 1/A Nature of material of conductor Temperature of conductor R𝖺l/A ρ – Constant of proportionality called Resistivity Unit of Resistivity – Ωm Metals and Alloys have very low resistivity whereas insulators have very high resistivity R= ρl/A

6. There are 2 ways of joining resistors together Series Parallel

7. Rs = R1 +R2 + R3

8. 1 /Rp = 1/R1 + 1/R2 + 1/R3

9. When an electric current flows through a wire, the wire heats up . Electrical energy has been converted into heat energy . The greater the resistance of the wire, the greater the amount of heat produced. This heating effect is used in common electrical appliances . I r on K e t t le

10. The work done in moving the charge Q through a potential difference V is VQ Therefore, the source must supply energy equal to VQ in time t. So, power input to the circuit by the source is P = V(Q/t) P=VI Energy supplied to the circuit by the source in time t is P × t or H= VIt H=I²Rt

11. In a light bulb, the heated filament which is also a resistance wire , becomes so hot that light is also emitted. Filament wire produces heat and light

12. A kettle uses both coppe r and nichrome wires. Copper has low resistance while nichrome has high resistance . Which material, copper or nichrome, should be used for the heating element, and for the external wire? Use copper wire for the external wire as it has low resistance & produces less heat Use nichrome wire for the heating element as it has high resistance& produces a lot of heat

13. THANK YOU