Question

(a) A concave mirror produces 3 times enlarged image of an object placed at
10cm in front of it. Calculate the focal length of the mirror.
(b) Show the formation of the image with the help of a ray diagram when an
object is placed 6cm away from the pole of the mirror.​

Answer 1

Answer:

Given,

Magnification, m=3

Object distance, u=10cm

We know,

Magnification, m=−uv

3=−10−v

⇒  v=30cm

From mirror formula,

f1=v1+u1

f1=301−101

=30×1010−30

=300−20

f=−15cm

Focal length, f=−15cm