P6 Waves

Question 1

Definitions

Amplitude
Wavlength
Frequency

Answer 1

Amplitude-maximum displacement of a point on the wave from its undisturbed position

Wavelength- the distance between the same point of 2 adjacent waves

Frequency- number of complete waves passing a certain point per second

Question 2

Explain

2 types of waves and an example

Answer 2

Transverse- Waves oscillate perpendicular to the direction of energy transfer. An example is all electromagnetic waves

Longitudinal- Waves oscillate parrallel to the direction of energy transfer. An example is sound waves

Question 3

Period equation

Answer 3

T=1/f

Period(s)= 1/frequency(Hz)

Question 4

Wave speed equation

Answer 4

v=f x wavelength

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

Question 5

Practical

How to measure wave speed in a liquid

Answer 5

Independent variable- Frequecny of waves
Dependent variable- Wavelength and wave speed
Control variable- Depth of water in ripple tank and shape of ripple tank

Set up ripple tank with a dipper that is attached parralell to the short side of the tank.
Below the ripple tank should be paper so place ruler on top so that wavelength can be measured
Take a photo so that you can count the distance of the wave then use v=f x wavelength to get wave speed

Question 6

How to measure wave speed in a solid

Answer 6

Suspend solid metal in the air.
Then hit solid with a hammer.
Then measure frequnecy
Then measure object with metre ruler then double that to get wavelength.

Question 7

Defintion

Angle of incidence
Angle of reflection
Normal

Answer 7

Angle between incoming wave and the normal

Angle between reflected wave and normal

Normal is a line thats perpendicular to the surface

Question 8

Diffuse
Specular reflection

Answer 8

Specular- When a wave is reflected in a single direction by a smooth surface.
Diffuse- When a wave is reflected by a rough surface and the rays go in different directions.
Makes objects appear matte
Due to the normal being different each time

Question 9

What increases and decreases across the EM wave spectrum

Answer 9

Increasing frequency
Decreasing wavelength

Question 10

Order of electromagnetic spectrum

Answer 10

Radio
Microwaves
Infra Red
Visible light
Ultra violet
X rays
Gamma rays

Question 11

Explain

Refraction

Answer 11

When waves cross boundary between materials at an angle it changes direction and its refracted.
The wavelength changes but not the frequency

Question 12

Practical

How to investigate reflection

Answer 12

Independent variable- Angle of incidence
Dependent variable-Angle of refraction
Control- Glass block, light source

Place light within ray box that has one slit allowing light to pass through. Then place glass block in front of ray box. Draw where the light source comes in and leaves the block. Then remove block and draw the angle of incidence and angle of refraction. Then meausere angle then repeat with different angles

Question 13

2 Uses of all EM waves

Answer 13

Radio-Communication/Navigation

Microwaves-Communication/Microwaves

Infrared- Electric heaters/ Infrared cameras

Visible light-Optical fibres/Illumination

Ultraviolet-Disinfection/Foresnics

X rays/Gamma rays- X rays/Chemotherapy

Question 14

Explain each

2 types of lenses

Answer 14

Concave- Lens cave inwards. It causes parallel rays of light to spread out. Its principal focus is before the rays hit the lens

Convex- Bulges outwards and causes rays of lights parallel to the axis to be brought together at the principal focus.