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?

Question

Responses

64%

156.25%

56.25%

36%

Answer 1

To find the efficiency of the space heater, we use the formula for efficiency, which is:

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

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

Now, we can calculate the efficiency:

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

Calculating this gives:

\[ \text{Efficiency} = \left(0.6400\right) \times 100% = 64% \]

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