MCQ ON RAY OPTICS : QUIZ RAY OPTICS PART-4

 

1/6

The focal length of a lens of power 2.5 dioptres is:

a) 5 cm

b) 1. 25 cm

c) 40 cm

d) 25 cm

Explanation: Power of a lens is a measure of the convergence or divergence produced by a lens. The power of a lens is defined as the reciprocal of the focal length. S.I unit of power = Dioptre (D) Power of lense = 1/ focal length in meter.

2/6

The phenomenon of total internal reflection is seen when angle of incidence is:

a) 90°

b) 0°

c) 45°

d)greater than or equal to critical angle

3/6

The focal length of a plane glass plate is infinite what will be power ?

a) 0

b) infinite

c) both a and b

d) None of these

4/6

Optical fibre is an application of

interference

total internal reflection

reflection

none of these

5/6

‘Mirage’ is a phenomenon due to:

a) Reflection of light

b) Refraction of light

c) Total internal reflection of light

d) Diffraction of light

6/6

A substance has critical angle 45 degree for yellow light. What is its refractive index?

μ = 1.414

μ = 2.414

μ = 3.414

none of these

Explanation: use formulae : μ =1/sin 45

Result: