Optics Answers

Distinguish between fringes of equal inclination and fringes of equal thickness

Derive an expression for the displacement of the nth bright fringe in Young’s

double-slit experiment when a thin transparent plate of refractive index  and

thickness t is introduced in the path of one of the constituent interfering beams of

light. Will there be any change in the fringe-width after the introduction of the

plate?

The electric field vectors of two light waves propagating along the positive zdirection

are given as

E₁(z,t) = xˆ E₀₁cos(kz - (omega)t)

E₂(z,t) = yˆ E₀₂cos(kz-(omega)t + (si))

where xˆ and yˆ are unit vectors along x and y-axes, respectively. Show that when

these two waves superpose, we obtain elliptically polarised light. Also show that

the linear and circular polarisations are special cases of elliptical polarisation

Determine the frequencies of the fundamental mode and the next two harmonics

that can be set up on a sitar string of length 1.0 m. Take the speed of waves of the

string to be 2.8 *10³ms^-1.

The mathematical expression for one dimensional wave travelling along the

positive x-direction is given as

y(x,t ) * 0.02 sin (42 x *1886t )m

where x is in meters and t is in seconds. Determine the direction of propagation of

the wave and calculate its amplitude, wavelength, frequency and velocity.

Internal critical angle in core at core-cladding interface of a step index fiber is 78.6°. The refractive index of cladding is 1.45. find acceptance angle

A step index fiber is made with a core of refractive index 1.36, a diameter of 49pm and a fractional refractive index change of 0.025. it is operated at a wavelength of 1.3. Then the numerical aperture of the cable is

A converging lens of focal length 0.40cm is combined with a diverging lens of focal length 0.20cm the power of combination of the lens is

resolving power of telescope

resolving power of microscope