Question

A 5 cm long object is placed in front of a concave mirror of radius of
curvature 40 cm. The distance of object from mirror is 40 cm. Find the
distance and size of the image.​

Answer 1

Answer:U=-200cm(since 20m)

h=5cm

r=40cm

So f= -20cm(since f=r/2 & concave mirror)

Now using mirror formula--

1/u+1/v=1/f

1/v=1/f-1/u

1/v=1/-20–(1/-200)

1/v=-9/200

v=200/-9=-22.2cm

So position of the image is 22.2cm to the left of the mirror.

Now,

magnification m=-v/u

h'/h=-v/u

h'/5=-(-22.2/-200)

h'=-(111/200)

h'=-0.56

Hence, sizeof the image is 0.56cm and is real and inverted.