Question

Suraj obtains an inverted image of height 7 cm of an object kept at a distance of 30 cm from a concave mirror. If the focal length of the mirror is 15 cm, find the height of the object.

7 cm

5 cm

3.5 cm

10 cm​

Answer 1

Answer:

7 cm

Explanation :

Image height, h' = -7cm

Object distance, u = - 30 cm

Focal length, f = -15 cm

1/v +1/u =1/f

1/v + 1/-30 = 1/-15

1/v =1/-15 - 1/-30

1/v = - 1/15 + 1/30

1/v = -2+1/30

1/v = - 1/30

v = - 30

M= h'/h = - v/u

- 7 /h = - - 30/ - 30

- 7/h = - 1

- 7 = - h

7= h

Therefore,

Object height, h =7 cm