Chapter 17, Problem 54A

To determine

The boy’s actual height.

Answer to Problem 54A

The actual height of a boy is 1.8 m.

Explanation of Solution

Given:

The height of the image of the boy, $h_i=0.60\text{}\text{m}$

Magnification of the mirror, $m=\frac{1}{3}$

Formula used:

Magnification, $m=\frac{h_i}{h_o}=-\frac{d_i}{d_o}$

Where,

  $\begin{array}{l}{h}_i=\text{image height}\\ h_o=\text{object height}\\ d_i=\text{ image distance}\\ d_o=\text{object distance}\end{array}$

Calculation:

Using the given values in magnification, the boy’s actual height will be,

  $\begin{array}{l}m=\frac{h_i}{h_o}\\ \frac{1}{3}=\frac{0.60}{h_o}\\ h_o=1.8\text{m}\end{array}$

Conclusion:

Therefore, the boy’s actual height is $1.8\text{m}$ .