Question

Rohit placed a pencil perpendicular to principal axis in front of a converging mirro of focal length 30cm. The image formed is twice the size of the pencil . Calculate the distance of the object from the mirror

Answer 1

Answer:

f = -30

h =2h

u=?

now ,

m= -v/u = h'/h

-v/u= 2

-v= 2u

v =-2u

We know that,

1/f= 1/v +1/u

1/-30=1/-2u+1/u

-1/30 = -1/2u +( -1 +2/2u)

-1/30= +1/2u

2u= -30 cm

u = -15