Question

If the potential difference applied to a fixed resistance is doubled, the power dissipated by that resistance

1. Remains the same
2. Doubles
3. Halves
4. Quadruples

Answer 1

The power dissipated by a resistor is

`P=I^2 R = (V^2)/(R)`
where I is the current, V the voltage and R the resistance.

We can see that if the voltage V is doubled and R is kept fixed, the new dissipated power is

`P' = ((2V)^2)/(R)= (4V^2)/(R)=4 P`
so, it quadruples.