Waves

Question 1

What is the definition of a pulse?

Answer 1

A single disturbance in a medium

Question 2

What is the definition of a transverse pulse?

Answer 2

A pulse in which the particles of the medium move at right angles to the direction of motion of the pulse

Question 3

What is the definition of an amplitude?

Answer 3

The maximum distance of a particle from its rest (equilibrium) position

Question 4

What is the definition of the principle of superposition?

Answer 4

The algebraic sum of the amplitudes of two pulses that occupy the same space at the same time

Question 5

What is the definition of constructive interference

Answer 5

The PHENEOMENON where the crest of one pulse overlaps with the crest of another to produce a pulse of increased amplitude

Question 6

What is the definition of destructive interference?

Answer 6

The PHENOMENON where the crest of one pulse overlaps with the trough of another, resulting in a pulse of reduced amplitude

Question 7

What is the definition of a transverse wave?

Answer 7

A wave in which the particles of the medium vibrate at right angles to the direction of motion of the wave. A transverse wave is a succession of transverse pulses

Question 8

What is the definition of wavelength?

Answer 8

The distance between two successive points in phase

Question 9

What is the definition of frequency

Answer 9

The numberof wave pulses per second

Question 10

What is the definition of a period

Answer 10

The time taken for one complete wave pulse

Question 11

What is the definition of amplitude

Answer 11

The maximum displacement of a particle from its equilibrium position

Question 12

What is the definition of a crest

Answer 12

The highest point (peak) on a wave

Question 13

What is the definition of a trough?

Answer 13

The lowest point on a wave

Question 14

Explain the wave concept, “in phase”

Answer 14

Two points in phase are separated by a whole number (1; 2; 3;…) multiple of complete wavelengths

Question 15

Explain the wave concept, “out of phase”

Answer 15

Points that are not separated by a whole number multiple of complete wavelengths

Question 15

What is the definition of wave speed

Answer 15

The distance travelled by a point on a wave per unit of time

Question 16

What is the definition of a longitudinal wave

Answer 16

A wave in which the particles of the medium vibrate parallel to the direction motion of the wave

Question 17

What is the definition of a compression

Answer 17

A region of high pressure in a longitudinal wave

Question 17

What is the definition of a rarefaction

Answer 17

A region of low pressure in a longitudinal wave

Question 18

Explain how sound waves are created

Answer 18

Sound waves are created by vibrations in a medium in the direction of propagation. The vibrations cause a regular variation in pressure in the medium

Question 19

Describe a sound wave/What type of wave is a sound wave?

Answer 19

A longitudinal wave

Question 20

What are echoes?

Answer 20

Echoes are reflections of sound waves

Question 21

How is the pitch of a sound related to the frequency of a sound wave?

Answer 21

Pitch is the effect produced in the ear due to the sound of a particular frequency. Pitch is directly proportional to frequency.

Question 22

How is the loudness of a sound related to both the amplitude of a sound wave and the sensitivity of the human ear?

Answer 22

Loudness is a subjective term describing the strength of the ear’s perception of a sound. Loudness is directly proportional to amplitude.

Question 23

How is the quality of sound related to the waveform as it appears to the listener?

Answer 23

Two notes of the same pitch and loudness, played on different instruments do not sound the same because the waveforms are different and therefore differ in quality or tone

Question 24

What are sounds with frequencies higher than 20kHz up to about 100kHz?

Answer 24

Ultrasound

Question 25

Explain how an image can be created using ultrasound

Answer 25

When a wave encounters a boundary between two media, part of the wave is reflected, part is absorbed, and part is transmitted.

Question 26

What are some of the benefits and uses of ultrasound?

Answer 26

Safety, diagnosis, treatment and pregnancy

Question 26

What are the two methods of explaining the behaviour of electromagnetic radiation?

Answer 26

Some aspects of the behaviour of electromagnetic radiation can best be explained using a wave model and some aspects can be explained using a particle model.

Question 27

Describe the source of electromagnetic waves

Answer 27

An accelerating charge

Question 28

How does an electromagnetic wave propagate?

Answer 28

An electromagnetic wave propagates when an electric field oscillating in one plane produces a magnetic field oscillating in a plane at right angles to it, which produces an oscillating electric field, and so on.

Question 29

What is the constant speed that mutually regenerating fields travel through space?

Answer 29

3×10^8 m.s^-2 as represented by c

Question 30

What are the properties of electromagnetic waves?

Answer 30

1. They originate from accelerating electric charges 2. Propagate as electric and magnetic fields that are perpendicular to each other 3. Can travel through a vaccuum 4. Have a speed of 3×10^8 m.s^-1

Question 31

What is the definition of a photon?

Answer 31

A packet of energy found in light

Question 32

Explain the dual nature of electromagnetic radiation

Answer 32

Explain that some aspects of the behaviour of electromagnetic radiation can best be explained using a wave model and some aspects can best be explained using a particle model.