Optics Answers

Let say you have two electromagnetic wave
y1=2sin(2πx −20πt)
y2=2sin(2πx −20πt+ϕ),
Assume that these to waves start to propagate at the same instant t_0.1=t_0.2=0sec, but at different initial positions from an observation point.
The amplitude of the resultant wave due to
interference of these to waves would be maximum at the observation point if the phase difference is how much?

The angle of acceptance of an optical fibre is 30 degree when kept in air. find the angle of acceptance when it is in a medium of refractive index 1.33

b) In the step index fiber the relative refractive index difference is=4% and n2 = 1.5 Find a) n1 b)Critical propagation angle c)N.A d)Maximum angle of incidence for guidance

With a laser, fringes remain clearly visible, when the path difference was increased up to X m, Deduce Coherence time and spectral half width given λ = 11.5x10-7 m.
X = 1.768 T = 77323

"An optical pump of wavelength λ1 nm is used for excitation of a laser of wavelength λ2 nm. If the pump has a power of X W, and if one in every 10 pump photons is absorbed by the laser crystal for the emission process, calculate the peak power of the laser and number of laser photons emitted per second
"
λ2 = 543.75 W = 13.84

Calculate the reflection coefficient R2 of the output coupler of L cm cavity tube of a laser of wavelength is 632.8nm which has the threshold gain factor and loss factor of 0.15 m-1 and 0.05m-1 respectively with one mirror of R1% reflecting.
L = 0.91 R1% = 98.62

What modifications are required for Laurent’s polarimeter if it is to be used for white light?

In Wallostons air film experiment, what will happen if we will use the mercury as a source of light

The material to be used for an antireflective coating has index of refraction of 1.25. How thick should the coating be to give the best result for l=550 nm and an angle of incidence of 30 degrees with the normal?

An object 0.04m high is placed in front of and at right angle to the axis of a concave mirror which has radius of curvature 0.15m. if a real image 0.12m high is obtained determine by scale drawing or otherwise the distance of the object from the mirror. How far and in what direction must the object be moved in order to obtain a virtual image 0.12m high.