Michelson Interferometer Experiment 15 Viva Questions | Interference

Last updated on Tuesday, October 3rd, 2023

 The Michelson Interferometer works on the interference principle. A beam splitter that is a semi-silvered glass plate used for this purpose. It works on the interference principle. “What is the principle of the Michelson Interferometer?”

Michelson Interferometer Experiment Viva Questions

Determination of He-Ne Laser wavelength by using the M I Experiment

The two interfering waves construct the interference pattern. The circular pattern of fringes depends upon the uniform thickness between the two mirrors.

1Q. Define what is Interference?

Interference is a phenomenon that occurs when two or more waves meet and combine, resulting in a new wave pattern. Depending on the phase relationship between the waves, interference can produce either constructive or destructive interference.

2Q. What is the condition for Interference?

For interference to occur, two or more waves must meet and overlap in space and time. The waves must have the same frequency and they must be coherent. Their phase difference must remain constant over time.

3Q. Explain the LASER properties and what do you mean by a Coherent Source?

The key properties of laser light include:
Coherence: light waves are all in phase with each other, and their phase difference remains constant over time.

Monochromaticity:

Laser light is highly monochromatic, it consists of only a single color or frequency.
Directionality: It is highly directional, meaning that it can be focused into a very narrow beam that travels over long distances with minimal spreading.
High intensity: Laser light is highly intense, it carries a large amount of energy per unit area.

A coherent source refers to a source of light that is highly coherent, the light waves are all in phase with each other and maintain their phase relationship over time.

4Q. Why you are using the LASER source, why not bulb or sunlight, tube light?

It is monochromatic, coherent and highly directional.

5Q. What is the role of a semi-silvered glass plate and why one keep it at 45 degrees?

The semi-silvered glass plate is usually oriented at a 45-degree angle relative to the incident beam. This orientation allows the incident beam to be split into two beams that travel along paths that are perpendicular to each other.

6Q. How do you think that a semi-silvered glass plate will look like?

A semi-silvered glass plate typically looks like a rectangular piece of glass with a partially reflective coating applied to one of its surfaces. The coating is usually a thin layer of metal. The thickness and composition of the coating determine the reflectivity and transmittance properties of the semi-silvered glass plate.

7Q. Why do you keep compensating plate in the path of the light ray, is it transparent or semi-silvered plate?

To make the the path of both light rays equal, so a constant phase difference.

8Q.  Is compensating plate of the same thickness as of semi -silvered glass plate or it is different?

Same thickness

9Q. What is the relation between path difference and phase difference?

The relation between path difference and phase difference is given by:

Phase difference = (2π / λ) x path difference

where λ is the wavelength of the light used in the experiment.

10Q. Which one is fixed mirror M1 or M2 in the Michelson Interferometer experiment?

In a Michelson interferometer experiment, the mirror M1 is typically fixed, while the mirror M2 is mounted on a movable platform that can be adjusted to change the path length of the sample beam.

11Q. M1 and M2 mirror are at 90 degrees or more?

The mirrors M1 and M2 in a Michelson interferometer experiment are typically placed at an angle of 90 degrees with respect to each other.

12Q. Where image forms using the M2 mirror by a semi-silvered glass plate?

In a Michelson interferometer experiment, the image of the mirror M2 formed by the semi-silvered glass plate depends on the angle of incidence of the incident beam on the plate.

13Q. Where thin film of air forms and how?

In a Michelson interferometer experiment, a thin film of air can form between the semi-silvered glass plate and the mirror M2 when the mirror is moved to change the path length of the sample beam.

14Q. How one can change the thickness of thin air film?

When the mirror M2 is moved away from the semi-silvered glass plate, the distance between the plate and the mirror increases. It creates a thin film of air between them. This thin film of air acts as a layer of low refractive index material, which causes a phase shift in the reflected beam that interferes with the original beam. By changing the mirror M2 position.

15Q. How the two light rays satisfy interference condition at eyepiece?

The two light rays, one from the reference arm and the other from the sample arm, travel different paths before they are recombined at the semi-silvered glass plate. The path difference between these two rays can be adjusted by changing the position of the mirror M2. 

Constructive-Destructive interference

When the path difference is an integer multiple of the wavelength, the two rays interfere constructively and produce a bright fringe at the eyepiece.

If it is a half-integer multiple of the wavelength, the two rays interfere destructively and produce a dark fringe at the eyepiece.

Attempt the quiz to LEARN MORE

QUIZ for PRACTICE:

These are the questions:

1. The two light waves in M.I. the experiment that satisfies the interference condition at eyepiece make a form?

 of random fringes

 of interference pattern as per the light source

 of circular fringes

 of maxima at different positions

2. What is the condition for colored Interference?

 The source should be monochromatic

 The source should be like Sun

 The source should be a LASER

 The source should be a red LED

3. Why you are using the LASER (monochromatic source) why not bulb or sunlight, tube light?

 to get the circular fringes

 to get the black and white fringe pattern

 to satisfy the interference condition

 to get all the waves in the same phase

4. How the velocity of light changes (once c-v and then c+v), what is the reason for it?

where c is the speed of light and v is the earth’s velocity.

 Light velocity changes relative to the speed of aether

 It remains constant

 c-v will be only due to the relative speed of the earth

 c+v will be only due to the relative speed of the earth

5. Why do you keep compensating plate in the path of the light ray, is it transparent or semi-silvered plate?

 To make light reflections, semi silvered plate,

 To make interference, semi silvered plate,

 To create path disturbance, transparent

 to make path equal, transparent

6. At which angle M1 and M2 mirror are fixed?

 at 90 degrees

 at 60 degrees

 change the position according to the lab

 keep it generally at 60 degrees but it can vary according to the lab situation.

7. why do we keep a semi silvered glass plate at 45 degrees?

 light enters into the apparatus

 light breaks up into two parts before entering into the apparatus

 Light reflects at 90 degrees

 for interference

8. Where thin film of air forms?

 in between M1 and M2(image)

 in between M2 and M1(image)

 at M2

 at eye piece

9. How one can change the thickness of thin air film?

 By moving the M1 mirror

 By moving the M2 mirror

 By moving the semi silvered glass plate

 By moving the transparent plate

10. What about compensating plate thickness? is it of the same thickness as semi silvered or varies place to place?

 different

 it varies for a different color

 position matter where we fix it in apparatus

 same thickness

11. Where image forms of the M2 mirror by a semi-silvered glass plate?

 towards M1

 towards eye

 at the screen

 not sure

12. To find the path difference between light rays we use?

 reflected light from one mirror

 reflected light from two mirrors

 interference between two rays

 create a glass slab in between the mirrors

13. Which one is fixed mirror M1 or M2 in the Michelson Interferometer experiment?

 M1

 M2

 both are fixed

 both are movable

14. How do we observe a reflected and transmitted light beam from a monochromatic source?

 by using He-Ne laser

 by using semi silvered glass plate

 By using two mirrors

 By using two glass plates

15. What is the condition to be Coherent Sources?

 the wavelength should be precisely defined of sources

 The frequency should be precisely defined of the sources

 All the waves should travel in a direction from all sources

 All the waves should start with the same phase from all sources

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DO you have any more questions?

What is the working principle of Michelson interferometer?
Which mirror is used in Michelson interferometer?
What is the pattern of Michelson interferometer?
Why is Michelson interferometer laser used?
What is the equation for Michelson?
What is the function of interferometer?
What are the 2 types of interference?
What are fringes in interferometer?
What is the wavelength of Michelson interferometer?
What are the types of fringes in Michelson interferometer?
What are the parts of Michelson interferometer?
What are the advantages of Michelson interferometer?