Waves 2

Question 1

What is the principle of superposition of waves?

Answer 1

When two waves meet at a point, the resultant displacement at that point is equal to the sum of the displacements of the individual waves.

Question 2

What is superposition?

Answer 2

When two waves of the same type meet and overlap.

Question 3

What is interference?

Answer 3

When two progressive waves continuously pass through each other and superpose to produce a resultant wave with a displacement equal to the sum of the individual displacement of the two waves.

Question 4

What is constructive interference?

Answer 4

When two progressive waves that are in phase produce a resultant wave that has a larger resultant amplitude than the two individual waves

Question 5

What is destructive interference?

Answer 5

When two progressive waves that are in antiphase produce a resultant wave with a resultant amplitude that is less that that of the two individual waves.

Question 6

What must the waves be to form a stable interference pattern?

Answer 6

Coherent

Question 7

What is coherence?

Answer 7

Refers to waves emitted from two sources having a constant phase difference and same frequency

Question 8

What is path difference?

Answer 8

The difference in distance travelled by two waves from their sources to the point where they meet.

Question 9

What do interference patterns contain?

Answer 9

A series of minima and maxima

Question 10

How does constructive interference occur in an interference pattern?

Answer 10

If the path difference is zero or a whole number multiple of the wavelength, the two waves will meet in phase so the resultant wave has max amplitude.

Question 11

How does destructive interference occur in an interference pattern?

Answer 11

When the path difference is an odd number of half wavelengths, the two waves will arrive in antiphase so the resultant wave has min amplitude.

Question 12

What is a stationary wave?

Answer 12

When two waves of the same amplitude and frequency superpose when travelling in opposite directions

Question 13

What is a node?

Answer 13

• Displacements of waves is zero
• Destructive interference
• Intensity is zero
• Amplitude is zero

Question 14

What is an antinode?

Answer 14

Opposite of node

Question 15

Phase differences along a stationary wave:

Answer 15

• In between adjacent nodes: all the particles are travelling in phase with each other
• On different sides of a node: the particles are in antiphase