Waves

Question 1

What is a wave?

Answer 1

A wave is the movement of energy

Question 2

What is a transverse wave?

Answer 2

When the displacement (vector version of distance) is at a right angle of the direction of the wave.

Question 3

What is a longitudinal wave?

Answer 3

When the displacement is parallel to the direction of the wave.

Question 4

What are compressions?

Answer 4

Areas of high pressure

Question 4

What are compressions?

Answer 4

Areas of high pressure

Question 5

What are refractions?

Answer 5

Areas of low pressure

Question 6

What is amplitude?

Answer 6

How high the wave is

Question 7

What is a wavelength? What is it measured in?

Answer 7

the distance between two corresponding points on the wave. It is measured in meters.

Question 8

What is frequency and what is it measured in?

Answer 8

Frequency is how many waves pass by every second, it is measured in hertz (Hz)

Question 9

What is a wavefront?

Answer 9

The crest (the top bit) of the wave viewed from above.

Question 10

How fast does an electromagnetic (EM) wave travel through a vacuum? How does it vary with different types of EM waves?

Answer 10

300,000,000m/s and it does not vary with any waves, they all travel at the same speed through a vacuum

Question 11

What are all the different types of electromagnetic waves IN ORDER?

Answer 11

Gamma rays 
X-Rays 
Ultraviolet 
Visible light 
Infrared
Microwaves 
Radio/TV

Question 12

What does light do when entering a more dense medium?

Answer 12

The light slows down and bends towards the normal

Question 13

What happens to light when it enters a less dense medium?

Answer 13

The light speeds up and bends away form the normal.

Question 14

Radio waves can also be used as carrier waves in order to send a signal, what is the process of this?

Answer 14

Radio waves are produced in a transmitter using oscillations.
The wave is then transmitted through the air.
The radio then turns the radio wave back into an electrical signal. The oscillating wave induces an oscillating electrical signal.

Question 15

Give two sources of radiation.

Answer 15

The sun, which sends a light wave.

Gamma radiation where the wave comes from inside the change in the nucleus.

Question 16

People that work with radiation a lot have to wear something that measures the radiation dosage, what is this called? What is radiation measured in

Answer 16

A dosimeter, which measures radiation in Sieverts (Sv), 1000 millisieverts is equal to 1Sv

Question 17

How can gamma radiation, x-rays and ultraviolet be dangerous?

Answer 17

Gamma radiation causes the mutation of cells and can lead to cancer.
X-rays can cause cell mutation and cancer (this is why doctors are not in the room when an x-ray is happening because constant exposure means higher risk of cell mutation)
Ultraviolet causes premature aging of the skin and skin cancer (which is why sunscreen is so important)

Question 18

Why can radio waves travel further distances after being refracted of the atmosphere?

Answer 18

This is because they suffer little absorption. This is why they are used to communicate with satellites.

Question 19

What is an example of Infrared being used in everyday life? Explain what it does.

Answer 19

A remote control send a signal which contains a set of digital codes which carry different instructions to the device its being sent to.

Question 20

What is a use of gamma rays and what are the dangers?

Answer 20

Treating cancer (by killing the mutated cells) but it can cause mutation of the healthy cells

Question 21

What is a use of x rays and what are the dangers?

Answer 21

medical uses but it can lead to cell mutation

Question 22

What is a use of ultraviolet and what are the dangers?

Answer 22

sun tanning but can lead to skin cancer.

Question 23

What is a use of visible light and what are the dangers?

Answer 23

Seeing things, fibre optic cables, there are no dangers (unless you look at the sun)

Question 24

What is a use of infrared and what are the dangers?

Answer 24

remote controls and heat transfer

Question 25

What is a use of microwaves and what are the dangers?

Answer 25

satellites and phones, heating food. There are very few dangers

Question 26

What is a use of TV/radio waves and what are the dangers?

Answer 26

Communication, there are very few dangers

Question 27

How do lenses use the idea of refraction?

Answer 27

When light enters a more dense medium it slows down.

Question 28

What is the reason we see certain colours?

Answer 28

We see certain colours because all the other colours have been absorbed by that object, white reflects all seven colours.

Question 29

What is a converging lense?

Answer 29

A lense that is thickest at the centre

Question 30

What is a diverging lense?

Answer 30

A lense that is thinnest at the centre.

Question 31

How does a converging lense refract light?

Answer 31

The light is refracted inwards and once it goes through the lense it meets at a focused point (a singular point). A real image or virtual image is formed, a real image can be seen on a screen whereas a virtual image cannot.

Question 32

How does a diverging lense refract light?

Answer 32

The rays of light are refracted outwards and a virtual image is always formed (in other words, the image does not actually exist)

Question 33

What happens when light hits glass, wood, a mirror and a rough surface?

Answer 33

Glass- transmission
Wood- absorption
Mirror - specular reflection (transmitted in a different direction)
A rough surface- Diffuse reflection

Question 34

What can filters be used for?

Answer 34

Filters can be used to block out all other colours by absorbing certain colours and letting others pass through.

Question 35

What is the difference between an transparent and a translucent object?

Answer 35

A transparent object is one that lets all light through, a translucent object is one that allows light through but blocks or absorbs some of it.