SaraNextGen.Com


A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source.  To get the sharp image again, the screen is shifted by a distance d.  Then d is:

a.

0.55 cm away from the lens

b.

1.1 cm away from the lens

c.

0.55 cm towards the lens

d.

0

 


Question ID - 50070 | SaraNextGen Answer

A convex lens is put 10 cm from a light source and it makes a sharp image on a screen, kept 10cm from the lens. Now a glass block (refractive index 1.5) of 1.5 cm thickness is placed in contact with the light source.  To get the sharp image again, the screen is shifted by a distance d.  Then d is:

a.

0.55 cm away from the lens

b.

1.1 cm away from the lens

c.

0.55 cm towards the lens

d.

0

 

1 Answer - 5876 Votes

3537

Answer Key : (a) -

- =  f = 5cm

Shift due to slab=t in the direction of incident ray

=1.5 =0.5

Again,

  =

   = 10.55 cm



SaraNextGen