4.4 - Waves

Question 1

What is a Progressive Wave?

Answer 1

A wave that transfers energy away from a source

Question 2

What is a Longitudinal Wave?

Answer 2

A wave where the oscillations are parallel to the direction of wave propagation

Question 3

What is a Transverse Wave?

Answer 3

A wave where the oscillations are perpendicular to the direction of wave propagation

Question 4

What is Wavelength?

Answer 4

The distance between two successive identical points that have the same pattern of oscillation. Measured in metres.

Question 5

What is Period?

Answer 5

The period of a wave is the time it takes for one complete pattern of oscillation to take place at any point. Measured in seconds

Question 6

What is Frequency?

Answer 6

The number of oscillations per unit time at any point. Measured in Hertz

Question 7

What is Displacement?

Answer 7

The distance any part of the wave has moved from its rest position

Question 8

What is Amplitude?

Answer 8

The maximum displacement of a wave from its rest position

Question 9

What is Phase Difference?

Answer 9

It concerns the relationship between the pattern of vibration at two points.

Question 10

What is the standard wave length of Radio and Microwaves?

Answer 10

Radio - 10^-1 - 10^4

Microwave - 10^-4 - 10^-1

Question 11

What is the standard wave length for Infra Red and Visible Light waves?

Answer 11

Infra Red - 7.4x10^-7 - 10^-3

Visible Light - 3.7x10^-7 - 7.4x10^-7

Question 12

What are the standard wavelength for Ultra Violet, X-Rays and Gamma Ray waves?

Answer 12

Ultra Violet - 10^-9 - 3.7x10^-7

X-Rays - 10^-12 - 10^-7

Gamma Rays - 10^-16 - 10^-9

Question 13

What is the Intensity of a progressive wave?

Answer 13

The rate at which energy is transferred from one location to another as the wave travels through space, perpendicular to the direction of wave travel. I=P/A

Question 14

What is Diffraction?

Answer 14

The spreading out of a wave after passing around an obstacle or through a gap

Question 15

How does a polarising filter produce plane-polarised light?

Answer 15

By selective absorption of one component of the incident oscillations - the filter transmits only the component of light polarised perpendicular to that direction

Question 16

What is a plane-polarised wave?

Answer 16

A wave in which the oscillations of the field and the direction of travel are confined to a single plane

Question 17

What is the principle of superposition?

Answer 17

When two or more waves of the same type meet, the resultant wave can be found by adding the displacements of the individual waves

Question 18

What is coherence?

Answer 18

Two waves with a constant phase relationship

Question 19

What is the order?

Answer 19

The number pattern, n, on either side of the central maximum

Question 20

What are nodes?

Answer 20

Points in a stationary wave at which there is no displacement of the particles at any time

Question 21

What is an antinode?

Answer 21

Points where the displacement of the particles in a stationary wave varies by the maximum amount

Question 22

When can we observe total internal reflection?

Answer 22

When light or an other electromagnetic radiation travels from a material of a higher refractive index to one of lower refractive index (I.e. water to air) and the angle of incidence is larger than the critical angle

Question 23

How do you find the period of a wave on an oscilloscope?

Answer 23

Distance between peaks x time base setting

Question 24

What does each horizontal division on an oscilloscope represent?

Answer 24

A unit of time

Question 25

What does each vertical division on an oscilloscope represent?

Answer 25

A unit of voltage

Question 26

What is Malus’ Law?

Answer 26

It states that when a perfect polariser is put in a beam of polarised light, the intensity, I, of the the light that passes through is given by I=I(max)cos^2x

Question 27

What is polarisation used for?

Answer 27

Stress Analysis, Sunglasses (reflected and scattered light) and Radio Transmission