A small object ab of size 1mm is kept at a distance of 40 cm form a concave mirror of focal length 30 cm. Make image of this object.

Explanation

Here ,object size is very small.so, this is case 1.
` u=-40 cm`
and ` f=-30 cm`
applying the mirror formula
` (1/v)+(1/u)=(1/f)`,we have
` (1/v)+(1/(-40))=(1/(-30))`
Solving this equation , we get
v=-120cm`
Further , m=-(v)/(u)=-(-120)/(-40)=-3`
`Now, L_1=m^2L_(@)=(9)(1 mm) =9mm`
Image diagram is as shown below.