MEDIUM
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In what ways optic fiber plays an important role in medicine?

Important Questions on Refraction of Light

EASY
Which of the following figures represent the critical angle?
MEDIUM

The diagram below shows a light source P embedded in a rectangular glass block ABCD of critical angle 42°. Complete the path of the ray PQ till it emerges out of the block. Write necessary angles.
 

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EASY
State one important factor which affects the critical angle of a given medium.
MEDIUM

A light ray travelling in glass medium is incident on glass-air interface at an angle of incidence θ. The reflected (R) and transmitted (T) intensities, both as function of θ, are plotted. The correct sketch is:

MEDIUM

The critical angle for glass is 45°  for the light of yellow colour. State whether it will be less than equal to or more than 45° for:
a. Red light
b. Blue light

HARD
Define the terms critical angle and total internal reflection. State two conditions necessary for total internal reflection to occur. Write down the relation for the critical angle in terms of refractive index. Draw diagrams to illustrate the critical angle and total internal reflection.
MEDIUM

In the given diagram a source of light S is placed at the bottom of a beaker containing water. Complete the diagram. (Critical angle for water to air is 48°)

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MEDIUM
A ray of light travelling in a transparent medium falls on a surface separating the medium from air at an angle of incidence of 45°. The ray undergoes total internal reflection. If n is the refractive index of the medium with respect to air, select the possible value(s) of n from the following:
EASY
If the angle of incidence is equal to critical angle, then the angle of refraction is 
MEDIUM

A swimmer inside water looks up at the sky through the surface of water. The sky is bright due to daylight. He can see:

HARD
(a) Figure below shows a cross-section of a ‘light pipe’ made of a glass fibre of refractive index 1.68. The outer covering of the pipe is made of a material of refractive index 1.44. What is the range of the angles of the incident rays with the axis of the pipe for which total reflections inside the pipe take place, as shown in the figure.
(b) What is the answer if there is no outer covering of the pipe?
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MEDIUM

The velocity of light in transparent media A and B separated by a plane boundary are 2.0×108 and 2.5×108ms1 respectively. The critical angle for a light ray passing from A to B at the boundary is:

HARD
What is meant by the statement the critical angle for diamond is 240?
EASY
Mirage is a best example for the phenomenon of 
MEDIUM

A ray of light travelling in a transparent medium of refractive index n falls, on a surface separating the medium from air at an angle of incidence of 45. The ray can undergo total internal reflection for which of the following n?

MEDIUM
The refractive index of glass with respect to air is 2. Then the critical angle of glass-air interface is _____.
EASY
Which of the following is not due to total internal reflection?
MEDIUM
The velocity of light in a medium is 1.5×108ms1. The critical angle c for a ray going from the medium into air is:
EASY
All organs of our body cannot be seen by naked eye. Optical fibre can be used to see the internal organs. An optical fibre cable is inserted into our stomach and light will be sent down through an optical fibre by the phenomenon called _____ of light. (total internal reflection / total internal refraction)