BE IT (Information Technology) Semester 2 (FE First Year) - University of Mumbai Question Bank Solutions for Applied Physics 2

Calculate the V number of an optical fibre having numerical aperture 0.25 and core diameter 20 μm, if its operating wavelength is 1.55 μm. 

With neat ray diagram explain the concept of total internal reflection (TIR). 

Obtain the condition for maxima and minima of the light reflected from a thin transparent film of uniform thickness. Why is the visibility of the fringe much higher in the reflected system than in the transmitted system.

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. 

Explain spherical co-ordinate system. State the transformation relation between Cartesian and spherical co-ordinates.

an electron is accelerated through a potential difference of 5kv and enters a uniform magnetic field of 0.02 wb/m² acting normal to the direction of electron motion. Determine radius of the path. 

The core diameter of 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.

What is meant by thin film? Comment on the colours in thin film in sunlight.

Derive the conditions of maxima and minima due to interference of light transmitted from thin film of uniform thickness.

Difference between step index and graded index fibre.
An optical fibre has a numerical aperture of 0.20 and refractive index of cladding is 1.59. Determine the core refractive index and the acceptance angle for the fibre in water which has a refractive index of 1.33.

Explain cylindrical co-ordinate system.
State the transformation relation between cartesian and cylindrical co-ordinates.

Using spherical co-ordinate systems calculate the area of a disc of radius 2 cm.

Differentiate between spontaneous and stimulated emission.

Find cylindrical co-ordinates of a point (3𝒊̅ + 4𝒋̅ + 𝒌̅) 

Derive the conditions of maxima and minima due to interference of light reflected from thin film of uniform thickness.

Derive the formula for numerical aperture of step index fibre and give it’s physical significance.The N.A of of an optical fibre is 0.5 and the core refractive index is 1.54.Find the refractive index of cladding.

Derive the formula for numerical aperture of step index fibre and give it’s physical significance.The N.A of of an optical fibre is 0.5 and the core refractive index is 1.54.Find the refractive index of cladding.

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

A glass material A with an optical fibre is made has a refractive index of 1.55. This material is clad with another material whose refractive index is 1.51. The light in the fibre is launched from air. Calculate the numerical aperture of the fibre.

An electron enters a uniform magnetic field B=0.23x10-2 Wb/m2 at 450 angle to B. Determine the radius and pitch of helical path. Assume electron speed to be 3x107 m/s.