A candle flame 1.6 cm high is imaged in a ball bearing of diameter 0.4 cm. If the ball bearing is 20 cm away from the flame, find the location and the height of the image.

Answer

A, B, C, D

Explanation

Height of the object AB=1.6 cm
diameter of the ball bearing =d=0.4cm
`rarr R=0.2cm`
Given `u=20cm`
`We know 1/v+1/u=2/R`
Putting the values according to sign conventions
`1/(-20)+1/v=2/2.0`
`rarr v=1` cminside the ball bearing.
Magnification =m
`=(A'B')/(AB) v/u`
`=(AB)/200=1/200`
`rarr A'B'=(AB)/200+1.6/200`
`=+0.008 cm`