Question

the image formed by convex mirror of focal length 20 cm is quarter of its object what is the distance of object from the mirror​

Answer 1

We can use the relation between magnification factor, focal length and distance of the image from the mirror to find out the distance of the object from the mirror

m=-(v/u)

adding 1 both sides

m+1 = 1-(v/u)

= (u-v)/u..............(i)

By using the mirror formula we can find out the value of (u-v) in terms of focal length f.

(1/v)-(1/u) = (1/f)

(u-v)/uv. = (1/f)

(u-v). = uv/f

substituting the value of(u-v) in equation(i)

m+1= (uv)/(fu)

m+1 = (v/f)

(1/4)+1= (v/20)

v= 25cm

Answer 2

the distance of object will be 100 cms left of the convex mirror .