Question

focal length=20cm
object distance = 5cm
find image distance ​

Answer 1

Answer:

25

Explanation:

Focal length =20cm and object distance =5cm then 20+5=25

Answer 2

Answer:

If it is mirror then answer is

= -20/3 cm

If it is lens then answer is

= 4cm

Explanation:

In mirror

1/V +1/U = 1/F

1/V = 1/F - 1/U

1/V = 1/20 - 1/5 = -3/20

V = -20/3

In lens

1/V - 1/U = 1/F

1/V = 1/F + 1/U

1/V = 1/20 + 1/5 = 1/4

V = 4cm

* V = distance of image

U = distance of object

F = focal length