Chapter 23, Problem 47P

(a)

To determine

The location of image.

Answer to Problem 47P

  $-72cm$ .

Explanation of Solution

Given info:

Focal length, $f=24cm$

Distance to the object, $d_o=18cm$

Formula used:

The equation of thin lens:

  $\frac{1}{d_o}+\frac{1}{d_i}=\frac{1}{f}$

Where,

  $f$ is focal length

  $d_o$ is distance to object

  $d_i$ is image distance

Calculation:

Substitute the given values in formula: $\frac{1}{d_o}+\frac{1}{d_i}=\frac{1}{f}$

  $\frac{1}{18cm}+\frac{1}{d_i}=\frac{1}{24cm}$

  $d_i=-72cm$

(b)

To determine

The magnification.

Answer to Problem 47P

  $4$ .

Explanation of Solution

Given info:

image distance, $d_i=-72cm$

Distance to the object, $d_o=18cm$

Formula used:

Formula to calculate the magnification:

  $m=\frac{-d_i}{d_0}$

Where,

  $m$ is magnification

  $d_o$ is distance to object

  $d_i$ is image distance

Calculation:

Substitute the given values in formula: $m=\frac{-d_i}{d_0}$

  $m=-\frac{-72}{18}=4$