Question

Two resistances R and 2R are connected in parallel in an electric circuit. The thermal energy developed in R and 2R are in the ratio
(a) 1 : 2
(b) 2 : 1
(c) 1 : 4
(d) 4 : 1

Answer 1

(b) 2 : 1

Thermal energy developed in the resistances,
H =$\frac{V^2}{R}t$
Heat developed in the resistance R, H₁=$\frac{V^2}{R}t$
Heat developed in the resistance 2R, H₂ = $\frac{V^2}{2R}t$

Thus, Heat developed in the resistance R and 2R are in ratio 2:1.