Question

An object 5 cm high is placed 20cm in front of a concave mirror

Answer 1

the question is incomplete please check it again

Answer 2

Object-size, h = + 5.0 cm;

Object-distance, u = – 20.0 cm;

Focal length, f = –15.0 cm;

Image-distance, v = ?

Image-size, h′ = ?

Mirror formula is             (1/v) + (1/u) = 1/f

1/v = (1/f) − (1/u)

     = (−1/15) + (1/20)

     = −1/60

v = − 60 cm.

The screen should be placed at 60 cm from the mirror. The image is real.

Magnification m = h'/h = − v/u = 60/(– 20) = – 3

Height of the image h' = mh = (– 3)x5 = − 15 cm

The image in inverted and enlarged.