Question

A 4cm long object is placed at a distance 20cm from a concave mirror of focal length 15cm. find the position size and nature of the image.

Answer 1

Explanation:

U=25cm

F=15cm

1/f=1/v+1/u

1/15=1/v+1/25

1/v=1/15-1/25

5/v=1/3-1/5(Divide everything by 5)

5/v=3-5/15 ( Cross multiply)

5/v=-2/15

v=-2/75(Multiply 5 and 15)

v=-75/2(Reciprocal)

v=-37.5

hi=-(37.5)×4/25

hi=6cm

The image is inverted,real and magnified