A rotating space heater used 1,400 joules of energy while heating a room. Of that total, 896 joules produced thermal energy, 181 joules produced kinetic energy, 203 joules produced light energy, and 120 joules produced sound energy. What is the space heater’s efficiency?(1 point)

Question

Responses

156.25%
156.25%

36%
36%

56.25%
56.25%

64%

Answer 1

To find the efficiency of the space heater, we need to determine the ratio of useful energy output to the total energy input.

In this case, the useful energy output is the thermal energy produced, which is 896 joules. The total energy input is 1,400 joules.

Efficiency (η) can be calculated using the formula:

\[ \text{Efficiency} (%) = \left( \frac{\text{Useful Energy Output}}{\text{Total Energy Input}} \right) \times 100 \]

Substituting the values we have:

\[ \text{Efficiency} = \left( \frac{896 , \text{joules}}{1400 , \text{joules}} \right) \times 100 \]

Calculating this:

\[ \text{Efficiency} = \left( \frac{896}{1400} \right) \times 100 \approx 64% \]

Thus, the space heater’s efficiency is 64%.