Question

An object is placed on the principal axis of a concave mirror of focal length 24 cm. If the image
distance is 20 cm more than the object distance, the magnification of the image is
[1]​

Answer 1

Explanation:

focal length = 24cm

image distance = 20cm

we know focal length formula :. 1/f=1/u+1/v

then we want to substitute it

1/24=1/u+1/20

1/u=1/24-1/20

1/u=20-24/480

1/u=-4/480

1/u=-1/120

then u= -120

magnification= -v/u

= -20/-120

= 1/60

= 0.0166666...

if it is wrong then u can consider another one

thankyou