Optics Answers

A transparent plastic has been developed. When light travels through it, it only travels at 3 × 107 m/s. What will be the refractive index of this new plastic?

1. Apply the concepts of light behaviours, refraction and image formation to explaining the physics of vision in the eye and the use of lenses to correct vision

2. Briefly discuss the concept of total internal reflection and fibreoptics for data and light transmission in medical applications

3. Compare the properties of laser light beams to light beams from conventional sources (e.g. light bulb) and briefly discuss the significance of the differences.

what is the highest order spectrum which may be seen with monochromatic light of wavelength 6000A by means of a grating spectrum 5000per lines

What is grating element?

A multimode step-index has a relative refractive index difference of 2% and a core refractive index of 1.5. The Number of modes propagating at a wavelength of 1.3um is 1000. Calculate:

a) The cladding refractive index

b) Numerical Aperture

c) The diameter of the fiber core

Convergence of concave mirror can be decreased by dipping in 

a. Water

b. Oil

c. Both water and oil

d. Cannot be decreased 

Light from a LED enters through the pupil of the eye whose diameter is 6.1 mm. If the intensity is 2.3x10-11 W/m2, calculate the power of light that enters into the eye. If the LED is replaced with a He-Ne LASER ((=632.8 nm) calculate the power if 1.7x1015 photons/s are emitted. Assume that the laser beams diameter and pupil size are the same.

Photons of wavelength 0.8 µm are incident on a p-n photodiode at a rate of 5 x 

10¹⁰ s-1 and on average the electrons are collected at the terminals of the diode at 

the rate of 1.5 x 10¹⁰ s-1. Calculate (a) The quantum efficiency (%) (b) band gap (in 

eV) of the semiconductor material and (c) the mean output photo current for 12 

µW incident optical power.