Question

5. An object at a distance of 30 cm from a concave mirror gets its image at the

same point. The focal length of the mirror is

(a) – 30 cm

(b) 30 cm

(c) – 15 cm

(d) +15 cm
​

Answer 1

Answer:

(d)+15 cm

Explanation:

Here's the explanation,

The focal length of mirror is 15 cm.

As object and image are located at the same point and in front of concave mirror then we take u = +30 cm and v = + 30 cm. f = + 15 cm. Thus, the focal length of mirror is 15 cm.