P5 Waves in Matter

Question 1

Refraction

Answer 1

When a wave travels from one medium to another and its velocity and direction change

Question 2

Reflection

Answer 2

Waves reverse direction

Question 3

Diffraction

Answer 3

Waves spread out

Question 4

Wave phenomena can only occur at…

Answer 4

The boundary between two media

Question 5

Wave phenomena can only occur when…

Answer 5

A wave changes speed

Question 6

The angle of incidence is equal to the angle of reflection

Answer 6

i=r

Question 7

What is ultrasound

Answer 7

The name given to sound waves with a frequency greater than 20,000Hz

Question 8

What is a wave?

Answer 8

Am oscillation that transfers energy

Question 9

Mechanical waves

Answer 9

Need a medium to travel through
e.g. sound and water

Question 10

Longitudinal

Answer 10

Direction of vibrations is parallel to direction of the wave
e.g. sound waves

Question 11

Transverse

Answer 11

Direction of the vibrations is perpendicular to the direction of the waves

Question 12

Frequency

Answer 12

Number of waves, or oscillations, per second

Question 13

Time period

Answer 13

Time taken for a wave to pass a point

Question 14

Wavelength

Answer 14

Distance from one point on the wave to the same point on the next

Question 15

Amplitude

Answer 15

Distance from the middle of the wave to the top (crest) or the bottom (trough) of the wave

Question 16

Wave Velocity (m/s)=

Answer 16

Frequency (Hz) x Wavelength (m)

Question 17

Vibrations of a transverse wave are perpendicular to the waves direction of travel. List some transverse waves.

Answer 17

EM waves
S-waves
Water waves

Question 18

List some longitudinal waves

Answer 18

Sound waves
P-wave

Question 19

How could you generate water waves at a fixed frequency in a ripple tank?

Answer 19

Use a dipper attached to a signal generator. The signal generator moves the dipper up and down at a constant frequency, which creates waves with the same frequency.

Question 20

How could you find the frequency of a water wave in a ripple tank using a cork and a stopwatch?

Answer 20

Float the cork on the water. Start the stopwatch when the cork is at the top of a ‘bob’ and count how many times the cork bobs with the waves in a set amount of time. Divide the number of bobs by the time interval (in seconds) to find the frequency.

Question 21

Why does milk appear white?

Answer 21

Because the particles scatter all wavelengths.

Question 22

Why does ink appear black?

Answer 22

Because the particles absorb all wavelengths.