Mechanical Waves

Question 1

What is the primary function of mechanical waves?

Answer 1

Transfer energy from one place to another without transferring matter.

Question 2

What are the two types of mechanical waves?

Answer 2

Transverse and longitudinal.

Question 3

What happens when a light object is dropped into still water?

Answer 3

It produces ripples (waves) on the water which spread out, but neither the object nor the water moves with the ripples.

Question 4

How do sound waves travel through air?

Answer 4

The voice box vibrates, making sound waves travel through the air without the air itself traveling away.

Question 5

What is required for mechanical waves to travel?

Answer 5

A substance (a medium).

Question 6

What are some examples of mechanical waves?

Answer 6

• Sound waves
• Water waves
• Waves on springs and ropes
• Seismic waves produced by earthquakes.

Question 7

What happens to particles in a substance when waves travel through it?

Answer 7

The particles oscillate (vibrate) and pass energy on to neighboring particles.

Question 8

What characterizes the oscillations of a transverse wave?

Answer 8

They are perpendicular (at right angles) to the direction in which the waves transfer energy.

Question 9

What is an example of a transverse wave?

Answer 9

Ripples on the surface of water.

Question 10

What characterizes the oscillations of a longitudinal wave?

Answer 10

They are parallel to the direction in which the waves transfer energy.

Question 11

What do longitudinal waves produce in a substance?

Answer 11

Areas of compression and rarefaction.

Question 12

What is an example of a longitudinal wave?

Answer 12

Sound waves in air.

Question 13

What is amplitude in wave motion?

Answer 13

Maximum displacement of a point on a wave from its undisturbed position.

Question 14

What does frequency measure in wave motion?

Answer 14

Number of waves passing a fixed point per second.

Question 15

What is the period of a wave?

Answer 15

Time taken for one complete wave to pass a fixed point.

Question 16

What is wavelength in wave motion?

Answer 16

Distance from one point on a wave to the equivalent point on the next wave.

Question 17

What is wave speed?

Answer 17

Distance travelled by each wave per second, and the speed at which energy is transferred by the wave.

Question 18

What is the unit of amplitude?

Answer 18

Metre (m).

Question 19

What is the unit of frequency?

Answer 19

Hertz (Hz).

Question 20

What is the unit of period?

Answer 20

Second (s).

Question 21

What is the unit of wavelength?

Answer 21

Metre (m).

Question 22

What is the unit of wave speed?

Answer 22

Metres per second (m/s).

Question 23

What is the relationship between frequency and period?

Answer 23

Period (T) = 1 / frequency (f)

Frequency is measured in Hertz (Hz) and period is measured in seconds.

Question 24

What is the wave equation?

Answer 24

Wave speed (v) = frequency (f) x wavelength (λ)

Wave speed is measured in meters per second (m/s), frequency in Hertz (Hz), and wavelength in meters (m).

Question 25

What happens to the frequency of a wave when it travels from one medium to another?

Answer 25

The frequency always stays the same ## Footnote However, the speed and wavelength may change.

Question 26

How can the speed of ripples on water be measured?

Answer 26

Speed (m/s) = distance (m) / time (s) ## Footnote A stopwatch and ruler can be used for measurement.

Question 27

How can the speed of sound in air be measured?

Answer 27

Using a stopwatch to measure the time taken for sound to travel a known distance ## Footnote The same speed equation is applied.

Question 28

What are the steps to draw a ray diagram for reflection?

Answer 28

* Use a ruler for lines * Draw an arrow for wave direction * Draw a dotted normal line at incidence point * Label normal, angle of incidence (i), and angle of reflection (r) ## Footnote A ray diagram visually represents the behavior of waves during reflection.

Question 29

What is the relationship between the angle of incidence and the angle of reflection?

Answer 29

i = r ## Footnote This principle is fundamental in the study of wave reflection.

Question 30

What happens when waves arrive at the boundary between two different substances?

Answer 30

* Absorption * Reflection * Refraction * Transmission ## Footnote These processes describe how waves interact with different materials.

Question 31

What is absorption in the context of wave behavior?

Answer 31

The energy of the waves is transferred to the energy stores of the substance they travel into ## Footnote An example is food being heated in a microwave.

Question 32

What is reflection in wave behavior?

Answer 32

Waves bounce back ## Footnote This is a common phenomenon when waves encounter a surface.

Question 33

What is refraction in wave behavior?

Answer 33

Waves change speed and direction as they cross the boundary ## Footnote This occurs due to differences in medium properties.

Question 34

What is transmission in wave behavior?

Answer 34

Waves carry on moving once they've crossed the boundary, but may be refracted ## Footnote This describes the continuation of wave propagation into a new medium.