2022 Current ElectricityHeating Effect of Current Easy Question 1 of 3 in Heating Effect of Current

Two resistors of resistance, $100\ \Omega$ and $200\ \Omega$ are connected in parallel in an electrical circuit. The ratio of the thermal energy developed in $100\ \Omega$ to that in $200\ \Omega$ in a given time is :

A $4:1$
B $1:2$
C $2:1$
D $1:4$

The answer is C.

Solution

In parallel, the potential drop V across both resistors is the same. $P = \frac{V^2}{R} \Rightarrow P \propto \frac{1}{R}$ $\frac{P_1}{P_2} = \frac{R_2}{R_1} = \frac{200}{100} = \frac{2}{1}$ So the ratio of thermal energies is 2 : 1.

Concept heat in parallel resistors

Heating Effect of Current in past papers

3 questions from this chapter have appeared across 3 exam years.