Waves - Chapter 6

Question 1

What is a wave?

Answer 1

The transfer of energy over a distance, in the form of a disturbance.

Question 2

What is periodic motion?

Answer 2

Motion that occurs when the vibration of an object is repeated over equal time intervals.

Question 3

What are the 3 basic types of vibration?

Answer 3

1. Transverse vibration
2. Longitudinal vibration
3. Torsional vibration

Question 4

What is transverse vibration?

Answer 4

When an object vibrates perpendicular to its axis.

Question 5

What is longitudinal vibration?

Answer 5

When an object vibrates parallel to its axis.

Question 6

What is torsional vibration?

Answer 6

When an object twists around it axis.

Question 7

What is a cycle?

Answer 7

One complete vibration.

Question 8

What is frequency?

Answer 8

The measure of the number of cycles per second.

Question 9

What is a period?

Answer 9

The time required for one cycle.

Question 10

What is an amplitude?

Answer 10

The distance from the equilibrium (rest) position to the point of maximum displacement.

Question 11

What does it mean to be vibrating in phase?

Answer 11

If the objects have the same period and pass through the rest/equilibrium position at the same time.

Question 12

What is a crest?

Answer 12

The high section in transverse waves.

Question 13

What is a trough?

Answer 13

The low section in transverse waves.

Question 14

What are periodic waves?

Answer 14

The motions are repeated at regular time intervals.

Question 15

What is a pulse/shockwave?

Answer 15

A single disturbance rather than periodic waves.

Question 16

What is the wavelength?

Answer 16

The distance between one crest to the next (or trough).

Question 17

What kind of waves does compression and rarefaction occur?

Answer 17

Longitudinal waves.

Question 18

What is rarefaction?

Answer 18

When the particles are further apart in longitudinal waves.

Question 19

When a wave is generated in a spring or a rope, how long does it take for the wave to travel one wavelength?

Answer 19

The time required for one complete vibration of the source.

Question 20

What is fixed-end reflection?

Answer 20

Reflection from a rigid obstacle when a pulse is inverted.

Question 21

What is free-end reflection?

Answer 21

Reflection where the new medium is free to move and there is no inversion.

Question 22

What is partial reflection?

Answer 22

Some of the energy is transmitted into the new medium and some is reflected back into the original medium.

Question 23

When a wave travels from one medium to another, when is the transmitted pulse inverted?

Answer 23

Never.

Question 24

When a wave travels from one medium to another, when is the reflected pulse inverted?

Answer 24

When the wave is traveling from a fast medium to a slow medium.

Question 25

What happens to the speed and wavelength of the wave when it travels from a fast medium to a slow medium?

Answer 25

The speed decreases and the wavelength of the wave decreases.

Question 26

What happens to the speed and wavelength of the wave when it travels from a slow medium to a fast medium?

Answer 26

The speed increases and the wavelength of the wave increases.

Question 27

What is a wavefront?

Answer 27

A line used to show the leading edge of a wave when drawing waves.

Question 28

What is a waveray?

Answer 28

An arrow indicating the direction.

Question 29

When do waves get reflected along their original path?

Answer 29

When they hit a barrier straight on.

Question 30

When is a wavefront reflected off the barrier at an angle?

Answer 30

When it runs into a straight barrier at an angle.

Question 31

What is the angle of reflection equal to?

Answer 31

The angle of incidence.

Question 32

What happens when a wave travels from deep to shallow water in such a way that it crosses the boundary at an angle?

Answer 32

The direction of the wave changes.

Question 33

What is refraction?

Answer 33

The bending effect on a wave's direction that occurs when a wave enters a medium at an angle.

Question 34

What else can cause waves to change direction?

Answer 34

When they pass the sharp edge of an obstacle or through a small opening.

Question 35

What is diffraction?

Answer 35

The bending effect on a wave's direction as it passes through an opening or by an obstacle.

Question 36

What does the amount of bending depend on with diffraction?

Answer 36

The wavelength and the size of the opening in the barrier.

Question 37

Does a smaller opening mean more or less diffraction?

Answer 37

More.

Question 38

What occurs when two waves act simultaneously on the same particles of a medium?

Answer 38

Wave interference.

Question 39

What is destructive interference?

Answer 39

Waves diminishing each other where the amplitude of the medium is less than it would have been for either of the interfering waves acting alone.

Question 40

What is constructive interference?

Answer 40

The waves build each other up resulting g in the medium having a larger amplitude.

Question 41

What does the Principle of Superposition state?

Answer 41

At any point, the resulting amplitude of two interfering waves is the algebraic sum of the amplitudes of the individual waves.

Question 42

What is mechanical resonance?

Answer 42

The transfer of energy from one object to another having the same natural frequency.

Question 43

What is a sympethetic vibration?

Answer 43

When an object vibrates in resonance with another.

Question 44

What are standing waves a special case of?

Answer 44

Interference.

Question 45

What is it called when conditions are controlled so that interfering waves have the same amplitude and wavelength but are traveling in opposite directions?

Answer 45

Standing waves.

Question 46

What is a node?

Answer 46

The point which remains at rest throughout the interference of the pulses of standing waves.

Question 47

What are nodes one half of?

Answer 47

The wavelength of the interfering waves.

Question 48

Where are antinodes?

Answer 48

Midway between nodes where supercrests and super troughs occur.

Question 49

What can we say about the waves produced from two vibrating sources attached to the same generator?

Answer 49

The wavelengths and amplitudes are the same and they are in phase.