When the potential difference across a resistive conductor of resistance R obeying ohm's law, is doubled, the rate of generation of heat will become

Question

Question

This question was previously asked in

ALP CBT 2 Physics and Maths Previous Paper 6 (Held On: 22 Jan 2019 Shift 3)

Answer 1

CONCEPT:

Resistance: The property of electrical materials and electrical instruments that opposes the flow of current through them is called resistance.
- It is denoted by R. The SI unit of resistance is the ohm (Ω).
Power: The rate of work done by an electric current is called power. It is denoted by P. The SI unit of power is the watt (W).

Power dissipation is given by:

Power (P) = V I = V2/R = I2 R

Heat generation (H) = (V²/R) t

Where V is the potential difference across resistance, I is current flowing and R is resistance.

CALCULATION:

Since Heat generation (H) = (V2/R) t

Potential is doubled, V' = 2 V

So new heat generation (H') = (V'2/R) t = ((2V)2/R) t = 4 (V2/R) t = 4 H

Hence option 4 is correct.