Question

An image of an object obtained by a convex mirror is 4 times
smaller than object. If the focal length of mirror is 20 cm,
the object distance would be
(A) 80 cm
(B) 40 cm
(C) 60 cm
(D) 100 cm​

Answer 1

Answer:

image distance =u=−20 cm

⇒: magnification

m=4=−v/u

so v=80 cm

from mirror formula

f1=v1+u1

f1=801−201

f=−0.0375 cm

Markas brainlist thanks

Answer 2

(B) 40cm

Here m=1/4

And f=+20 (given)

So the lens will be Convex now by applying magnification formula you can find value of u with respect to v

Then keeping this value in Lena formul...

We will get the answer.....