Question

A concave mirror is to form an image of an object on a screen, 4m from the mirror. The image is

to be magnified 80times. What should be the radius of curvature of the mirror and where is the

object to be placed? ​

Answer 1

Answer:

For mirror u=  

m

f(m−1)

​  

 

In first case, u=  

−4

f(−4−1)

​  

 

In the second case, u+3=  

−3

f(−3−1)

​  

 

On solving, we get f=36cm

Explanation: