U2.4.1-2.4.7 Superposition, Interferance And Diffraction

Question 1

What is the principle of superposition

Answer 1

When two or more waves meet at any point the resultant displacement at the that point is equal to the vector sum of the individual displacements due to each wave at that point

Question 2

What happens when two waves of the same amplitude overlap in anti-phase

Answer 2

They cancel each other. This is known as total destructive interference.

Question 3

If two waves meet and they are not of the same amplitude but do meet in anti-phase what happens

Answer 3

Destructive interference takes place and the resultant wave has a smaller amplitude.

Question 4

What makes two wave sources coherent

Answer 4

They must produce the same type of wave that have the same frequency (or wavelength) and they must maintain a constant phase difference.

Question 5

Standing waves:

Answer 5

The energy is not transferred but stored within the vibrating particles. It is created when two waves meet that are of equal frequency, amplitude and travelling at the same speed in opposite directions.

Question 6

What is a node

Answer 6

A point on a standing wave with 0 displacement.

Question 7

What is an anti-node

Answer 7

A point in a standing wave with maximum periodic displacement.
I.e. maximum amplitude

Question 8

What is resonance

Answer 8

It occurs when the frequency of the driving system matches the natural frequency of the system being vibrated and the I’ll produce vibrations with a large amplitude of vibration