Question

A plane mirror is made of glass slab $({\mu }_g=1.5)$ 2.5 cm
Thick and silvered on back. A point object is placed 5 cm in front of the unsilvered face of the mirror. What be the position of final image?

• A. 12.5 cm from unsilvered face
• B. 14.6 cm from unsilvered face
• C. 5.67 cm from unsilvered face
• D. 8.33 cm from unsilvered face

Answer 1

The correct option is A 12.5 cm from unsilvered face



Let $I_1,I_2$ and $I_3$ be the images formed by
(i) refraction from ABC
(ii) reflection from DEF and
(iii) again refraction from ABC
Then $B{I}_1=\left(5\right){\mu }_g=\left(5\right)\left(1.5\right)=7.5cm$
Now $E{I}_1=(7.5+2.5)=10cm$
$\therefore$ $E{I}_2=10$ cm behind the mirror