Superposition

Question 1

What is polarisation?

Answer 1

Confinement of oscillations in a wave to one direction in a plane perpendicular to the direction of transfer of energy.

Question 2

State the principle of superposition.

Answer 2

When two or more waves of same kind meet at a point at the same time, the resultant displacement of the wave is the vector sum of displacements due to each wave.

Question 3

What is diffraction?

Answer 3

It is bending or spreading of waves when they pass through an obstacle or an aperature.

Question 4

What is meant by coherence?

Answer 4

Having constant phase difference.

Question 5

How is observable fringes achieved?

Answer 5

1. Coherent waves with constant phase difference
2. Waves must meet
3. Waves have approximately equal amplitudes
4. Waves must be either unpolarised or polarised in the same plane

Question 6

What is interference?

Answer 6

Occur when two or more coherent waves meet and superpose to produce a new resultant wave.