Question

a spherical mirror forms an erect image of size half the size of the object placed in front of the mirror at a distance 15cm from it..
(i)name the type of mirror
(ii)state whether the image is real ot virtual
(iii)find position of image
(iv) calculate focal length of the mirror​

Answer 1

Answer:

I) Convex mirror

ii) Image is virtual

iii) We know that size of image is half that of the object hence magnification will be 1/2

So, m=1/2

m= -v/u

We know object distance is 15, hence u= -15

So, 1/2 = -v/-15

1/2 = v/15

15/2 = v Or v=7.5

Hence image is formed behind the mirror.

iv) 1/f = 1/v+1/u

1/f = 2/15 + (-1/15)

1/f = 1/15

Hence f = 15cm