Question

A 5 cm object is 18.0 cm from a convex lens, which has a focal length of 10.0 cm.

What is the distance of the image from the lens? Round your answer to three significant figures. ____ cm
What is the height of the image? Round your answer to three significant figures? ____ cm

Answer 1

Answer:

Image distance, v = 22.5 cm

Height of the image, h' = 6.5 cm

Explanation:

It is given that,

Height of the object, h = 5 cm

Object distance, u = -18 cm

Focal length of the lens, f = +10 cm

Using mirror's formula :

$\dfrac{1}{f}=\dfrac{1}{v}-\dfrac{1}{u}$

$\dfrac{1}{v}=\dfrac{1}{f}+\dfrac{1}{u}$

$\dfrac{1}{v}=\dfrac{1}{10}+\dfrac{1}{(-18)}$

v = 22.5 cm

Magnification of the lens :

$m=\dfrac{v}{u}=\dfrac{h'}{h}$

$h'=\dfrac{v}{u}h$

$h'=\dfrac{22.5\ cm}{-18\ cm}\times 5$

h' = -6.5 cm

Hence, this is the required solution.

Answer 2

Answer:

22.5  and 6.25

Explanation: