Module 4 - Waves (Phase and the Wave Equation)

Question 1

Define phase

Answer 1

how far through a wave cycle a particular point on the wave is

Question 2

Define Phase Difference

Answer 2

The difference in displacement of points on different waves or along the same wave

Question 3

Define In Phase

Answer 3

If two points on a wave both reach their positive and negative amplitude at the same time

Question 4

Define Antiphase

Answer 4

If two points on a wave reach their positive amplitude as the other reaches their negative amplitude

Question 5

When is a point on a wave out of phase with another

Answer 5

When it is neither in phase or in antiphase with anotehr point on a wave

Question 6

What is the Phase Difference Equation

Answer 6

Seperation between 2 points on a wave X (360 or 2π ) / Wavelength
φ = x/λ X (360 or 2π )

Question 7

What is meant by coherence

Answer 7

When 2 waves have a constant phase difference

Question 8

How do you know if two points are in phase in degrees

Answer 8

If the degree value is an even number multiple of 180

Question 9

How do you know if two poiints are in antiphase in degrees

Answer 9

If the degree value is ab odd number multiple of 180

Question 10

How do you know if 2 waves are in phase

Answer 10

Two waves are in phase if all points on one wave are in phase with the corresponding points on the other wave.

Question 11

What factor doesnt affect phase difference

Answer 11

The amplitude or the displacement at a given time

Question 12

What is the wave equation

Answer 12

v = fλ

Question 13

Derive the wave speed equation

Answer 13

v = distance travelled per unit time
f = number of wavelengths per unit time

wavelength - the distance of one complete oscillation

So if f –> the number of wavelengths per unit time and wavelength is just a distance of 1 wave cycle

v = fλ –> Distance travelled per unit time