Question

When an object is placed 20cm from a concave mirror , a real image magnified three times is formed. Find:

(a) focal length of the mirror.

(b) where must the object be placed to give a virtual image three times the height of the object?

Answer 1

........here is the answer

Answer 2

U=-20cm

M=3

M=-v/u

-3= - v/ - 20

V= -60

1÷f= 1÷v + 1÷u

1÷f = 1/-60+1/-20

After taking LCM...

We get f= -15

ii) b/w pole and focus