P12 Wave Properties

Question 1

What are the differences between P waves and S waves?

Answer 1

• P waves are longitudinal and can travel in liquids and
  solids
• S waves are transverse and cannot travel in liquids

Question 2

Name 3 types of seismic waves

Answer 2

P waves
S waves
Surface Waves (Longitudinal)

Question 3

What medium do P waves travel faster in?

Answer 3

They travel in solids faster than liquids

Question 4

What is the “S wave shadow”?

Answer 4

A place where only P waves are received, as the S waves cannot travel through the liquid outer core

Question 5

What are the 4 layers of the Earth?

Answer 5

Crust (solid earth and rock)
Mantle (solid)
Outer core (liquid iron and nickel)
Inner core (solid iron and nickel)

Question 6

Why is the inner core a solid despite being hotter than the outer core?

Answer 6

There is a greater pressure on it

Question 7

Why do P and S waves change direction gradually inside the earth?

Answer 7

As there is a gradual change in density, causing the waves to refract, changing their speed, and therefore their direction

Question 8

Where does the largest change in direction of a seismic wave inside the earth occur, and why?

Answer 8

At the boundary between the mantle and inner core, as there is the greatest change in density

Question 9

How does the amplitude of a wave relate to how much energy it contains?

Answer 9

The larger the amplitude, the larger the energy it carries

Question 10

What is refraction?

Answer 10

A wave changing direction after entering a new medium

Question 11

What is the range of hearing for humans called?

Answer 11

The auditory range (20-20,000Hz)

Question 12

What are ultrasound waves?

Answer 12

Waves with a frequency greater than 20,000Hz

Question 13

What is a special feature of ultrasound waves?

Answer 13

They partially reflect at the boundary between two different densities

Question 14

What does a wave transfer?

Answer 14

Energy from one place to another

Question 15

What causes a wave?

Answer 15

A vibration

Question 16

What is the definition of a transverse wave?

Answer 16

A wave whose oscillations are perpendicular to the direction of energy transfer

Question 17

What is the definition of a longitudinal wave?

Answer 17

A wave whose oscillations are parallel to the direction of energy transfer

Question 18

What is a compression?

Answer 18

When the particles in a longitudinal wave are closest together

Question 19

What is a rarefaction?

Answer 19

When the particles in a longitudinal wave are furthest apart

Question 20

Give 3 examples of longitudinal waves

Answer 20

• P waves
• Sound waves
• Ultrasound waves

Question 21

Give 3 examples of transverse waves

Answer 21

• S waves
• Water waves
• All electromagnetic waves

Question 22

What the period of a wave?

Answer 22

The time it takes for a wave to complete one full oscillation

Question 23

What is the frequency of a wave?

Answer 23

The number of waves passing a point each second

Question 24

What direction from the normal do waves bend when they slow down?

Answer 24

When waves slow down they bend towards the normal

Question 25

What direction from the normal do waves bend when they speed up?

Answer 25

When waves speed up they bend away from the normal

Question 26

In what instance do waves not refract when entering a different medium?

Answer 26

When the waves meet/leave the medium at a right angle to the surface

Question 27

Why is the frequency range of the human ear limited?

Answer 27

The conversion of sound waves to vibrations of solids only works over a limited frequency

Question 28

Name the mediums that light travels fastest to slowest in

Answer 28

Gases, liquids, then solids

Question 29

Name the mediums that sound travels fastest to slowest in

Answer 29

Solids, liquids then gases

Question 30

What is the speed of sound?

Answer 30

343m/s

Question 31

What are mechanical waves?

Answer 31

Waves that require a medium to propagate | Transverse and Longitudinal

Question 32

Describe a method to measure the speed of waves on a string

Answer 32

- Connect a string over a pulley to a vibration transducer - Connect a power pack/signal generator to vibration transducer and turn it on - Adjust frequency of generator to produce clear waves on the string - Count number of wavelengths on the string and divide by the distance they occupy to calculate mean wavelength - Use v = fλ to calculate speed of the wave