Waves- Basics

What are progressive waves?

Progressive waves transfer energy from one place to another, without transferring matter(/particles)

What are 2 types of progressive waves?

1. Transverse waves

2. Longitudinal waves

What are transverse waves?

Transverse waves oscillate perpendicular to the direction of propagation of the wave

What are longitudinal waves?

Longitudinal waves oscillate parallel to the direction of propagation of the wave

What are examples of transverse waves?

1. Water waves

2. EM waves

3. S-waves

What are examples of longitudinal waves?

1. Sound waves

2. P-waves

What is displacement?

Distance from a point on the wave to the equilibrium

What is amplitude?

Maximum displacement from the equilibrium

What is wavelength?

Minimum distance between 2 points in phase

What is time period?

The time taken for one complete oscillation

What is frequency?

The number of cycles per unit time

What is wave speed?

The distance travelled by a wave per unit time

What is the formula relating frequency and time period?

1. Frequency = 1 / time period

2. f = 1 / T

What is the formula for wave speed?

1. Wave speed = distance / time

2. Wave speed = frequency x wavelength

1a. v = d / t

1b. v = fλ

Derivate the equation for wave speed

1. For one complete cycle, wave speed = λ / T

2. Wave speed = λ x 1 / T

3. Therefore, wave speed = λf

What does phase difference mean?

The phase difference describes how far out of sync two points on a wave are

What is the formula for phase difference?

1. Φ = (x/λ) x 360*

2. x is the distance between the 2 points on the wave

If the phase difference is 180*, what does this mean?

1. The peak of one wave will meat the trough of the other wave

2. The waves will differ by 1/2 wavelength

What is intensity?

The intensity is the power transmitted per unit area

What is the equation for intensity?

1. Intensity = Power // croess-sectional area

2. I = P / A

What is the unit for intensity?

1. Wm^-2

2. W/m^2

Describe the relationship between intensity and distance

Intensity and distance share an inversely proportional relationship

Describe the relationship between intensity and amplitude

1. Intensity and amplitude share an proportional relationship.

2. I = k(A)^2

What is the equation to calculate the intensity of light in a sphere?

Intensity = Power // 4pir2

List all the waves in the EM spectrum from shortest to greatest wavelength

1. Gamma rays

2. X-rays

3. Ultraviolet rays

4. Visible light

5. Infrared

6. Microwaves

7. Radio waves