Chapter 12, Problem 53R

To determine

To Find: Efficiency of the incandescent lightbulb.

Answer to Problem 53R

The efficiency of the bulb is $83.33\%$ .

Explanation of Solution

Given:

Total power of lightbulb is $\text{60}\text{W}$

Energy deliver $\text{50J}$

Formula Used:

Efficiency of light bulb

  $\mu \text{=}\frac{\text{usefull}\text{energy}\text{out}}{\text{total}\text{energy}\text{in}}\text{×100}$  ...... (1)

Here, $\mu$ is the efficiency.

Calculation:

  $\text{60}\text{W=60J}$

Substitute $50\text{J}$ for $\text{usefull}\text{energy}\text{out}$ and $60\text{J}$ for $\text{total}\text{energy}\text{in}$ in equation (1)

  $\begin{array}{l}\mu =\frac{usefullenergyout}{totalenergyin}\times 100\\ \mu =\frac{50}{60}\times 100\\ \mu =83.33\%\end{array}$

Conclusion:

Hence, the efficiency of the bulb is $83.33\%$ .