Question

A bulb rated 60 W operates for 2 hours. How much energy does it consume in this time?

• A. 120 J
• B. 1200 J
• C. 720 J
• D. 4320 J

Hint:

Remember: The energy consumed by an electrical appliance is calculated by multiplying the power by the time.

Answer 1

The Correct Option is D

Given: The power of the bulb is \( 60 \, \text{W} \), and the time of operation is \( 2 \, \text{hours} \). Step 1: Convert time to seconds Since \( 1 \, \text{hour} = 3600 \, \text{seconds} \), the total time is: \[ t = 2 \times 3600 = 7200 \, \text{seconds} \] Step 2: Formula for energy Energy is given by the formula: \[ E = P \times t \] where: - \( P \) is the power in watts, - \( t \) is the time in seconds. Step 3: Substitute the values Substitute the given values into the formula: \[ E = 60 \times 7200 = 432000 \, \text{J} = 4320 \, \text{kJ} \] Answer: The correct answer is option (4): 4320 J.