Question

A bulb is marked 60 W and 240 V. Find the resistance in the bulb.

• A. 40 Ω
• B. 180 Ω
• C. 960 Ω
• D. 60 Ω

Answer 1

The Correct Option is C

To solve the problem, we need to find the resistance of the bulb given its power and voltage.

1. Use the Power Formula:
The power \( P \) of an electrical device is related to voltage \( V \) and resistance \( R \) by the formula:
\[ P = \frac{V^2}{R} \] where \( P \) is the power in watts, \( V \) is the voltage in volts, and \( R \) is the resistance in ohms.

2. Rearranging the Formula to Solve for Resistance:
Rearranging the formula to find resistance:
\[ R = \frac{V^2}{P} \]

3. Substituting the Given Values:
Given \( P = 60 \, \text{W} \) and \( V = 240 \, \text{V} \), substitute these values into the formula:
\[ R = \frac{(240)^2}{60} = \frac{57600}{60} = 960 \, \Omega \]

Final Answer:
The resistance of the bulb is \( 960 \, \Omega \).