waves

Question 1

Polarised light

Answer 1

Light in which the OSCILLATIONS of the ELECTROMAGNETIC FIELD are all in a SINGLE PLANE

Question 2

Explain why two coherent sources of light that are polarised in planes perpendicular to
each other will not produce interference fringes.

Answer 2

The displacements due to the two waves are in perpendicular axes, thus their vector sum
will not be able to produce maxima and minima, since they can never be in the same or
in opposite directions

Question 3

One of the polarisers is rotated by an angle of 45⁰ about an axis parallel to the
incident light. Describe the appearance of the fringes with reference to its original
appearance.

Answer 3

(Only the components of the light waves that are oscillating in parallel planes will
interfere to form maxima and minima. The components that are oscillating in
perpendicular planes will not be affected by each other.) Thus the maxima will be
less bright and the minima will be brighter.
The fringe separation remains the same as before.

Question 4

What is polarization

Answer 4

Polarization refers to CONFINING the oscillation to one direction only, that direction being at right angles to direction of transverse wave energy

Question 5

Longitudinal wave

Answer 5

Longitudinal wave is a

1) disturbance in a medium in which the
2) DISPLACEMENT of the particles in the medium are
3) parallel to the direction of transfer of wave energy

Question 6

What is a wave

Answer 6

A wave is a disturbance in a medium which causes energy to be carried from one point to another by means of vibration and oscillations

Question 7

What is a transverse wave

Answer 7

Transverse wave is one where the displacement of the particles in the wave are at right angles to the direction of transfer of wave energy

Question 8

Intensity

Answer 8

Intensity of a wave is defined as the rate of energy flow per unit cross sectional area perpendicular to the direction of wave propagation