A point object at 15 cm from a concave mirror of radius of curvature 20 cm is made to oscillate along the principal axis with amplitude 2 mm. The amplitude of its image will be

Options

A. `2 mm`
B. `4 mm`
C. `8 mm`
D. `16 mm`

Answer

Converging; real

Explanation

Using mirror formula,
`(1)/(-10)=(1)/(v)+(1)/(-15) , implies v=-30cm` .
| Axial magnification| `=(V^(2))/(u^(2))=((30)/(15))^(2)=4`
amplitude of image `=4xx2=8mm` .