Question

An object 5 cm high is placed at a distance 60 cm in front of a concave mirror of focal length 10 cm. Find (i) the position and (ii) size, of the image.

WhatsApp

Answer

Given,

Object height (O) = 5 cm

focal length (f) = 10 cm (negative)

Object distance (u) = 60 cm (negative)

1\over u + 1\over v = 1\over f

⇒ – 1\over 60 + 1\over v =  – 1\over 10

1\over v = – 1\over 10 + 1\over 60

1\over v = - 6 + 1\over 60 = – 5\over 60   = – 1\over 12

⇒ v = -12 cm

The image distance (v) = 12 cm infront of the mirror.

I\over 5=-12\over 60

⇒ I = –12\over 60 × 5 = – 1 cm

Hence, length of image = 1 cm

Negative sign shows that the image will be inverted.

Was this answer helpful?

Didn't liked the above answer ?

≫ Some Related Questions