3 Waves

Question 1

Transverse Wave

Answer 1

Oscillates perpendicular to the direction of travel and energy

Question 2

Longitudonal Wave

Answer 2

A wave in which oscilates parallel to the direction of travel and energy

Question 3

Amplitude

Answer 3

The maximum displacement of a point of a wave from rest point

Question 4

Frequency

Answer 4

The number of waves that pass through a point each second. Mesured in hertz (Hz)

Question 5

Wavelength

Answer 5

Distance covered by a full cycle of a wave. Measured from crest to crest in metres (M).

Question 6

Time period

Answer 6

The time taken for a full cycle of a wave

Question 7

Wavefront

Answer 7

This is an imaginary surface that we draw to represent the vibrating part of a wave

Question 8

How do waves transfer energy

Answer 8

Waves transfer energy without transferring mass

Question 9

Calculate wave speed

Answer 9

wave speed (m/s) = frequency (Hz) x wavelength (m)

Question 10

Calculate frequency

Answer 10

frequency (Hz) = 1 / time period (s)

Question 11

Calculate time period

Answer 11

time period (s) = 1 / frequency (Hz)

Question 12

Doppler effect

Answer 12

Can be observed when a wave is moving relative to the observer. There is a change in wavelength and frequency. At the front there is a small wavelength and high frequency. At the back there is a long wavelength and a low frequency.

Question 13

Waves and order of the electromagnetic spectrum

Answer 13

Radio waves
Microwaves
Infrared
Visible light
Ultraviolet (UV
X-ray
Gamma rays

As you go down frequency increases and wavelength decreases.
They are transverse

Question 14

Uses of waves in electromagnetic spectrum

Answer 14

• radio waves: broadcasting and communications
• microwaves: cooking and satellite transmissions
• infrared: heaters and night vision equipment
• visible light: optical fibres and photography
• ultraviolet: fluorescent lamps, detecting forged bank notes
• x-rays: observing the internal structure of objects and materials, including for
  medical applications
• gamma rays: sterilising food and medical equipment.

Question 15

Dangers of waves

Answer 15

• microwaves: internal heating of body tissue
• infrared: skin burns
• ultraviolet: damage to surface cells and blindness
• gamma rays: cancer, mutation

Question 16

Law of reflection

Answer 16

Angle of incidence (i) = angle of reflection (r)

Question 17

Total Internal Reflection (TIR)

Answer 17

Light bounces off a boundary instead of going through it. This happens when angle i is greater than critical angle. Only happens when traveling from more dense to less dense

Question 18

When angle i is equal to critical angle…

Answer 18

Refracted ray carries along the boundary

Question 19

Refraction

Answer 19

When angle i is smaler than critical angle

From less dense to more dense, towards normal
From more dense to less dense, away from normal

Question 20

Critical angle

Answer 20

• sin critical angle = 1 / refractive index
• Bigger than 20º

Question 21

Refractive index

Answer 21

• Refractive index(n) = 1 / sin critical angle
• Refractive index(n) = sin i /sin r
• No unit: Only number/ratio
• Bigger than 1

Question 22

Sound waves…

Answer 22

• Longitudinal
• Can be refracted or reflected

Question 23

Hearing range for humans

Answer 23

20 Hz - 20000 Hz

Question 24

Relationship between frequency and pitch

Answer 24

The higher the frequency, the higher the pitch

Question 25

Relationship between amplitude and loudness

Answer 25

The bigger the amplitude, the louder

Question 26

Oscilloscope

Answer 26

An osciloscope displays waves

Question 27

Order of colours in visible light

Answer 27

Red
Orange
Yellow
Green
Blue
Indigo
Violet

As go down frequency increases and wavelength decreasess

Question 28

Electromagnetic spectrum

Answer 28

A continuous series/spectrum of waves with identical properties

They all travel at 300000000 km/s
They all transfer energy
They are all transverse
They can be reflected and refracted

Question 29

Angle of incidence

Answer 29

• sin angle of incidence = sin angle of refraction x n

Question 30

Angle of refraction

Answer 30

• sin angle of refraction = sin angle of incidence / n