20 Physics -- Reflection at Plane Surfaces

Write any five application of total internal reflection and explain.

1 Answers

The application of total internal reflection are as follows:

1. To deviate a ray of light through 90°.

A totally reflecting prism is used to deviate the path of ray of light through 90°, when it is inconvenient to view the direct light. In Michelson's method to find the velocity of light, the direct viewing by making use of totally reflecting prism.

2. To deviate a ray of light through 180°.

By deviating a ray of light through 180°, totally reflecting prisms are used in prism binoculars to produce an erect image or to correct for lateral inversion.

3. Mirage

It is an optical illusion observed in deserts and coal-tarred roads on hot days. The object such as a tree appears inverted and the observer gets the impression as if the inverted image has been formed by a pool of water. This phenomenon is known as mirage.

4. The brillance of diamonds and other precious stones. The refractive index of diamond is 2.47 and the critical angle for diamond air interface is 23° only. Due to low value of critical angle, a diamond can be cut so as to have a large number is faces, such that the ray if light on entering it from one faces undergoes repeated total internal reflections from other faces. As a result the faces through which the light emerges, shine very brilliantly.

5. Optical fibers.

Optical fibers are used to transmit light from one place to the other along a curved path in a more effective manner. The optical fibers consists of thousands of strands of a very fine quality glads or quatz consists of thousands of strands of a very fine quality glass or quartz of refractive index about 1.7, the thickness of a strand is about 10^-6cm, the strands are coated with a layer is some material of lower refractive index (about1.5). The ends of the strands are polished and clamped firmly after aligning them carefully.

At which angle of incidence , lateral shift of light on passing through rectangular glass slab is maximum?

a ray reflected successively from two plane mirrors inclined at a certain angle undergoes a deviation of 300. Then the angle isa) 30 b) 60 c) 90 d 120

B A D= x

, ABD=yHere AD and BD are Normal lines,

O B A = 90 y

O A B = 90 x

Δ O A B;

θ + 90 y + 90 x = 180

x + y = θ

Total deviation is

2 (90 x) + 2 (90 y)

= 360 2 (x + y)

= 360 2 θ

Here from the question deviation angle is 300^olet, a be the angle between two plane mirror, therefore, 300^o = 360^o - 2a so, a= 30^o

A diamond ring is placed inside a liquid. If the critical angle is found to be 37.40 and the refractive index of liquid is given to be 1.47, find the refractive index of diamond.

Refractive index of diamond is 2.42.

Solution:

We have,

i_c = 37.40

mu_liquid = 1.47

mu_diamond = ?

The critical angle is given for diamond-liquid interface. It is applicable for a ray of light passing from diamond through the liquid and out of this interface. When we apply these conditions and related formula, we get to our answer.

Let mu be the refractive index of diamond-liquid interface then,

mu = mu_diamond/mu_liquid

We know,

mu = 1 / sin(i_c)

= 1 / sin (37.4)

= 1.65

Now,

Using the fact:mu =...

Minimum height of plane mirror required to observe image of a man of height 6ft is 3ft when man's 1 m apart from the mirror . Is the size of image affected when distance between man and mirror is i...

In order to see full image of a person, the minimum size of the mirror should be one half the person’s height. This is so because, in reflection, the angle of incidence is equal to angle of reflection. So, to see the image of a 6 ft tall person, a 3 ft long mirror is required.

Which parameters of light do not change on refraction?

Upon refraction, the wavelength of the light ray changes but its frequency remains the same. Due to unchanged frequency, the energy possesed by the ray also does not change.

WHAT IS THE CORRECT RELATIONSHIP BETWEEN REFRACTIVE INDICES N, N1 AND N2 IF THE BEHAVIOR OF LIGHT IS AS SHOWN IN THE FIGURE? N1 > N N1 < N N1 = N.N2 N1 > N^2

Within a glass slab , a double convex air bubble is formed . How would the air bubbles behave ?

Within a glass slab, a double convex air bubble would behave as a converging lens. It would refract light, causing the light rays passing through it to converge, resulting in the formation of a real, inverted, and diminished image.

To a fish under water viewing obliquely, a fisherman standing on the bank of a lake , does the man look taller or shorter that what he actually is ?

To a fish viewing obliquely from underwater, the fisherman standing on the bank of a lake appears taller than he actually is. This is due to the refraction of light at the water-air interface, causing the fish to perceive an apparent upward displacement of the image.

ask mattrab