Question

A body of length 6 cm is placed 10cm from a concave mirror of focal length 20cm. Find the position, size, and nature of the image.

Answer 1

Consider the situation shown in the figure below which also includes the coordinate system.
Here, ` u=-10cm`
`f=-20cm`
Subtituting in the equation,
`(1)/(v)+(1)/(u)=(1)/(f)` , we get
`v=+20 cm`
Thus, the image is formed 20 cm behind the mirror, magnification `+2` , erect and virtual.