Question

7.A concave mirror has a 7.0-cm focal length. A 2.4cm tall object is 16.0cm from the mirror. Determine the image height.​

Answer 1

The height of the image (hi) is 0.73 cm

Given:

Focal length of concave mirror (f ) = 7.0 cm

Object distance (u) = - 16 cm

Height of the object (ho) = 2.4 cm

To Find:

Image height (hi)

Solution:

according to the mirror formula,  $\frac{1}{f} =\frac{1}{v} +\frac{1}{u}$

here,

$\frac{1}{7} =\frac{1}{v} -\frac{1}{16}$

$\frac{1}{v} =\frac{1}{7} +\frac{1}{16}$

$\frac{1}{v} =\frac{23}{112}$

   ${v} =4.87$ cm

According to the magnification formula,

$m=\frac{-v}{u} =\frac{hi}{ho}$

$\frac{hi}{ho} =\frac{4.87}{16}$

$hi=\frac{4.87}{16} *2.4=0.73$

therefore the height of the image (hi) is 0.73 cm