Chapter 6 - General waves + sound waves

Question 1

What do waves do

Answer 1

Transfer energy without transferring matter

Question 2

What are the 2 types of waves
How to particles vibrate

Answer 2

Transverse - Particles vibrate perpendicular to the direction of propagation of the wave.
Longitudinal - Particles vibrate parallel to the direction of propagation of the wave.

Question 3

How does the wave travel

Answer 3

Longitudinal - compressions and rarefactions
Transverse - crests and troughs.

Question 4

What is an oscillation

Answer 4

to-and-fro movement of a particle

Question 5

What is frequency
Unit

Answer 5

Number of waves passing any point per second

Hertz (Hz)

Question 6

What is wavelength

Answer 6

Distance between 2 consec crests or compressions.

Question 7

What is amplitude

Answer 7

The maximum displacement of any point in the wave from its rest position.

Question 8

What is the wave eqn
What is proportional to what

Answer 8

V = F * Lambda

V prop wavelength
F inv prop velocity

Question 9

Relation between frequency and time

Answer 9

1/time

Question 10

Where do transverse and longitudinal waves travel

Answer 10

Transverse - Solids and surface of liquids
Longitudinal - can travel through solids, liquids and gasses.

Question 11

What is time period

Answer 11

Time needed to produce one complete wave.

Question 12

What is reflection

Answer 12

Travelling back of a wave falling on a surface into the same medium

Question 13

What is diffraction

Answer 13

The bending of waves around the sides of an obstacle or spreading of waves as they pass through a gap

Question 14

What is reffraction

Answer 14

The change of direction of waves due to a change in speed of the waves.

Question 15

When is diffraction significant.

Answer 15

If the size of the gap is comparable to the wavelength.

Question 16

examples of transverse waves

Answer 16

light, water, seismic S-waves

Question 17

examples of longitudinal waves

Answer 17

sound waves

Question 18

what is a transverse wave and properties of them

Answer 18

-Travelling waves in which oscillation is perpendicular
to the direction of travel
-light waves
-Has crests and troughs

Question 19

what is a longitudinal wave and properties of them

Answer 19

-Traveling waves in which oscillation is parallel to the direction of travel.
-sound waves
-Has compressions and rarefactions

Question 20

what occurs in refraction from deep-shallow

Answer 20

Speed and wavelength are reduced
frequency stays the same and the wave changes direction

Question 21

when a wave is slowed down how does it refract

Answer 21

towards the normal
the angle of incidence > angle of refraction

Question 22

when a wave is sped up how does it refract

Answer 22

away from the normal
angle of incidence < angle of reflection

Question 23

what happens to waves as they move from deep to shallow water

Answer 23

speed decreases, wavelength decreases
frequency remains constant

Question 24

what happens to waves as they move from shallow water to deeper water

Answer 24

speed increases, wavelength increases
frequency remains constant

Question 25

refractive index from rarer to denser

Answer 25

sin i/sin r

Question 26

refractive index from denser to rarer

Answer 26

sin r/sin i

Question 27

refractive index formula (general)

Answer 27

speed of light in air/speed of light in medium 2

or c/v
c = speed of light in air = 3 x 10^ m/2
v = speed of light in medium 2

Question 28

frequency of ultrasound waves

Answer 28

35000 hz

Question 29

approximate range of hearing of a normal human ear

Answer 29

20Hz to 20kHz

Question 30

approximate speed of sound in air

Answer 30

340 m/s

Question 31

Definition of echo

Answer 31

reflection of sound waves

Question 32

Formula of echo

Answer 32

2d/t

where d = distance travelled
t = time taken

Question 33

Uses of ultrasound

Answer 33

nondestructive testing of materials

medical scanning of soft tissue

sonar - calculation of depth or distance from time and wave speed

Question 34

How would a diagram of compressions and rarefactions change if you need to show

higher frequency
louder sounds

Answer 34

frequency:
compressions and rarefactions move closer together

louder - layers (wavefronts) are closer together at C and further apart at R