BE Electronics and Telecommunication Engineering छमाही २ (इंजीनियरिंग) - University of Mumbai Important Questions for Applied Physics 2

Explain Newton’s ring experiment and show that diameters of nth dark rings are proportional to square root of natural numbers.

What is antireflection coating? What should be the refractive index and minimum thickness of the coating?

A parallel beam of light of wavelength 5890 A0 is incident on a glass plate having refractive index 𝝁=𝟏.𝟓 such that the angle of refraction in the plate is 600. Calculate the smallest thickness of the glass plate which will appear dark by reflected light.

With the help of proper diagram and necessary equation, explain how Newtons ring experiment is useful to determine the radius of curvature of plano convex lens. In a newton rings experiment the diameter of 5th dark ring is 0.336 cm and the diameter of 15th ring is 0.590 cm. Find the radius of curvature of plano convex lens if the wavelength of light used is 5890 A0.

What is diffraction grating and grating element? Explain experimental method to determine the wavelength of the spectral line using diffraction grating?

Derive the condition for absent spectra in grating.

A newtons rings setup is used with a source emitting two wavelength λ1=6000A0 and λ2=4500 A0. It is found that nth dark ring due to 6000A0 coincides with (n+2)th dark ring due to 4500 A0. If the radius of curvature of the lens is 90 cm, find the diameter of nth dark ring of 6000A0.

What is pumping in LASER? Give the types of pumping.

Explain construction and working of Nd: YAG laser. 

What is holography? Differentiate between holography and photography.

What is population inversion? Explain it’s significance in the operation of LASER.

Explain construction and working of He:Ne laser with neat label diagram. 

Explain the construction and reconstruction of hologram with neat diagram. 

Differentiate between spontaneous and stimulated emission.

What is the difference between photography and holography?
Explain holography technique to obtain 3D image of an object. 

Explain construction and working of Nd:YAG LASER. 

Write difference between LED and Laser Diode.

With a neat energy level diagram describe the construction and working of He-Ne Laser. What are the merits and demerits?

Differentiate between spontaneous and stimulated emission.

What is Numerical aperture? Explain the use of optical fibre in temperature sensor. The core diameter of a multimode step index fibre is 50 μm. The numerical aperture is 0.25. Calculate the number of guided modes at an operating wavelength of 0.75 μm.