Question

Glycerine (refractive index 1.4) is poured into a large jar of radius 0.2 m to a depth of 0.1 m. There is a small light source at the centre of the bottom of the jar. Find the area of the surface of glycerine through which the light passes.  

Solution

Correct option is

0.0327 m2

 

Let S be the light source. If light falls on the surface at critical angle c, it grazes along the surface, as shown. Now,

                   

from the figure, we have

                                         

             

  

The area of the surface through which light passes is

               

SIMILAR QUESTIONS

Q1

Two plane mirrors are inclined to each other such that a ray of light incident on the first mirror and parallel to the second is reflected from the second mirror parallel to the first mirror the angle between the two mirrors is   

Q2

A man 1.8 m tall wishes to see full-length image in a plane mirror. The length of the shortest mirror in which he can see his entire image is  

Q3

An illuminated object is placed between two plane mirrors mutually perpendicular to each other how many images are formed?

Q4

A 2.0 cm tall object is placed 15 cm from a concave mirror of focal length 10 cm. How far is the image from the mirror? 

Q5

An object 1.0 cm tall is placed 8 cm in front of a concave mirror of radius of curvature 24 cm. What is the size and the nature of the image?

Q6

A concave mirror forms a real image four times the size of the object placed at a distance of 10 cm from it. What is the radius of curvature of the mirror?   

Q7

In Young’s double slit experiment, the 10th maximum of wavelength λ1 is at a distance y1 from its central maximum and the 5th maximum of wavelength λ2 is at a distance y2 from its central maximum. The ratio y1/y2will be   

Q8

White light is used to illuminate the two slits in Young’s double slit experiment. The separation between the slits is d and the distance between the screen and the slit is D (>> d). At a point on the screen directly in front of on the slits, certain wavelengths are missing. The missing wavelengths are (here m = 0, 1, 2, … is an integer)     

Q9

In Young’s double slit experiment using two identical slits, the intensity of the maximum at the centre of the screen is I. What will be the intensity at the centre of the screen if one of the slits is closed?   

Q10

A ray of light travelling in glass (refractive index, ang = 3/2) is incident on a horizontal glass-air surface at the critical angle c. If a thin layer of water (refractive index, anw = 4/3) is now poured on the glass-air surface, at what angle will the ray of light emerge into air at the water-air surface?