Question

A 2.5 cm candle is placed 12 cm away from a convex mirror of focal length 30 cm. Give the location of the image and the magnification.

Answer 1

Correct Answer - 8.6cm ; 1.8cm
Here, `h_(1) = 2.5 cm, u = -12 cm, f = 30 cm, v = ?, m = ?`
As `(1)/(v) + 1/u = (1)/(f), (1)/(v) - 1/12 = 1/30`
or `(1)/(v) = 1/30 + 1/12 = (2+5)/60 = 7/60` or `v= 60/7 = 8.6 cm`
Positive sign of v shows that the image is virtual.
`m = (h_(2))/(h_(1)) = -v/u = - 60/(7xx(-12))` or `(h_(2))/(2.5) = 5/7 `or `h_(2) = 1.8 cm`.