Question

an object is placed at a distance of 60 cm from a concave mirror, the magnification produced is 1/2 where the object should be placed to get a magnification of 1/3​

Answer 1

Explanation:

1/f=1/v+1u

given u=60cm

also m=-v/u

1/2=-v/60

v=-30cm

1/f=-1/30+1/60

f=-60cm

in second case m=1/3

1/3=-v/u

u=-3v

-1/60=1/-3v+1/v(applying mirror formula)

-1/60==-2/3v

v=40

u=40/3cm