A refrigerator uses 150W. If it is kept on for 336 hours non-stop, what is the energy consumed in KWh?

1. Analyze the question

We are given the power rating of a refrigerator in Watts (W) and the time it runs in hours (h). We need to calculate the total energy consumed and express it in Kilowatt-hours (KWh).

2. Explain the concept

Energy ($E$) is defined as the product of Power ($P$) and Time ($t$):

To get the answer in KWh, we must ensure:

• Power is in Kilowatts (KW). To convert Watts to Kilowatts, divide by 1,000.
• Time is in hours (h).

3. Show the solution

Step 1: Convert Power from Watts to Kilowatts

Step 2: Identify the Time

Step 3: Calculate Energy

4. Identify the answer

Comparing our result ($50.4\text{ KWh}$) to the given options, it matches option B.

5. Exam Tip

Always check the units requested in the question! If the question asks for KWh, convert your power to KW first. If it asks for Joules, ensure your power is in Watts and your time is in seconds ($E = P \times t$).