Question

an object 8.25 cm from a lens creates a virtual image of magnification 2.40 what is the focal length of the lens (mind your minus sign) (unit=cm)

Answer 1

Answer:

Focal length of the lens is 14.14 cm

Explanation:

As we know that the image formed due to lens is virtual image

so here we have

M = 2.40

now we have

$\frac{d_i}{d_o} = 2.40$

now we have

distance of object is 8.25 cm

so we have

$d_i = 8.25(2.40) = 19.8 cm$

now by lens formula

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

$\frac{1}{-19.8} - \frac{1}{-8.25} = \frac{1}{f}$

$f = 14.14 cm$