Question

Two electric bulbs whose resistances are in the ratio 1:3 are connected in parallel to a constant voltage source. The powers dissipated in them have the ratio.

• A. 1:1
• B. 1:3
• C. 3:1
• D. 1:9

Answer 1

The correct option is C

3:1

Step 1: Given data,

The ratio of resistance given is $\frac{R_1}{R_2}=\frac{1}{3}$

The voltage across the resistance is the same.

Step 2: Calculate the power ratio,

$$\begin{gathered} Power=\frac{V^2}{R} \\ Therefore,\frac{P_1}{P_2}=\frac{R_2}{R_1}=\frac{3}{1} \end{gathered}$$

Hence, the answer is an option (C) i.e. 3:1.