Question

10. One face of glass cube of refractive index 1.5 and
Side 6 cm is silvered. An object is placed at a
distance 7 cm from the face opposite to the
Silvered face. Image of object behind the silvered -
face is at
(1) 18 cm
(2) 9 cm
(3) 10 cm
(4) 8 cm​

Answer 1

Given that,

Refractive index = 1.5

Side of cube = 6 cm

Distance = 7 cm

We need to calculate the image of object behind the silvered face

Using formula of refractive index

$\mu=\dfrac{\text{real depth}}{\text{apparent depth}}$

$\mu=\dfrac{d}{d'}$

Put the value into the formula

$1.5=\dfrac{6}{d'}$

$d'=\dfrac{6}{1.5}$

$d'=4$

We need to calculate the Image of object behind the silvered face

Using formula of image distance

Image distance = object distance + (Real depth - apparent depth)

$d_{image}=7+(6-4)$

$d_{image}=9\ cm$

Hence, The Image of object behind the silvered face is 9 cm.

(2) is correct option.