question_answer

A point object is placed at a distance of 30 cm from a convex mirror of focal length 30 cm. The image will form at

A) Infinity             

B) Focus

C) Pole                             

D) 15 cm behind the mirror

Correct Answer: D

Solution :

\[\operatorname{u} =-\,30 cm,\,\,f= + 30 cm\], by using mirror formula \[\frac{1}{f}=\frac{1}{\nu }+\frac{1}{u}\,\,\,\,\Rightarrow \,\,\,\frac{1}{+30}=\frac{1}{\nu }+\frac{1}{(-30)}\] \[\operatorname{v} =15 cm\], behind the mirror