P6 - Waves

Question 1

Electromagnetic spectrum list lowest frequency - highest fruequency GO

Answer 1

Radio waves, micro waves, infrared, visible light, ultra violet, x-rays, gamma rays

Question 2

Longitudinal waves travel perpendicular to the direction of travel

Answer 2

False. Transverse waves do. Longitudinal waves travel parallel to the direction of travel

Question 3

What is the definition of frequency?

Answer 3

How many waves pass in one second

Question 4

Waves transfer…

Answer 4

Energy

Question 5

What is the opposite of compression?

Answer 5

Rarefaction

Question 6

Which of these waves are transverse?

a) sound
b) light
c) sea
d) slinky (forwards)

Answer 6

b) light

c) sea

Question 7

The larger the amplitude the ______ the sound

Answer 7

Louder

Question 8

Which is the fastest wave in the electromagnetic spectrum in a vaccum?

Answer 8

They all travel at the same speed

Question 9

Microwaves, visiable light and radio waves can all be used for communications. True or false?

Answer 9

True

Question 10

Why does more scientific research need to go into WiFi? Give 2 reasons

Answer 10

It has only been around for a short period of time, so more research needs to go in to check it’s safe for people to be around

Question 11

How can EM (Electromagnetic) radiation be dangerous?

Answer 11

When it enters a living tissue, whilst it’s often harmless, sometimes it can cause damage such as sunburn, blindness, skin cancer, gene mutation and cancer (When high frequency waves like UV, x-rays and gamma rays are emitted)

Question 12

What is the units for radiation dose?

Answer 12

Sieverts. This is not a measure of the total amount of radiation that has been absorbed, it measures the risk of harm from the body being exposed to radiation

Question 13

How many millisieverts is a sievert?

Answer 13

1000mSv = 1Sv

A siervert is pretty big, so it is often in millisierverts

Question 14

What does a CT scan do?

Answer 14

Uses X-rays and a computer to build up a picture inside the patients body.

Question 15

When evaluating the risk of using any type of EM radiation (mainly X-rays), what can be said about the risk for different body parts?

Answer 15

The risks are different in different parts of the body

Question 16

Waves transfer energy where?

Answer 16

In the direction that they are travelling in

Question 17

Give some examples of transverse waves

Answer 17

All electromagnetic waves
Ripples and waves in water
A wave on a string

Question 18

Give some examples of longitudinal waves

Answer 18

Sound

Before an earthquake

Question 19

Give the formula for wave speed

Answer 19

Wavespeed = frequency x wavelength
m/s  =  Hz x m

Question 20

How can you measure a period? What is this?

Answer 20

28 day– ha no, that’s biology. In physics, a period is the amount of time it takes for a full cycle of a wave
It is found with 1/frequency (in hertz)

Question 21

What are the 2 different parts of longitudinal waves called?

Answer 21

Rarefactions - where the vibrations are spread out

Compressions - where the vibrations are close together

Question 22

Give the difference between transverse and longitudinal waves

Answer 22

Transverse waves - the oscillations (vibrations) travel perpendicular to the direction it is travelling in
Longitudinal waves - the oscillations travel parallel to the direction it is travelling in
Also, pretty sure that longitudinal waves can involve particles colliding in that pattern - like sound, but transverse waves never have particles. They are just waves of energy

Question 23

How can you measure the speed of sound?

Answer 23

Using an oscilloscope

It should be 330m/s

Question 24

330m/s is what?

Answer 24

Roughly the speed of sound

Question 25

How can you use a ripple tank to measure the speed of water ripples?

Answer 25

1) Using a vibrating bar connected to a power pack/ a signal generator attached to a dipper, submerged in a ripple tank (tray of shallow water). Also, have a light above it, and white paper beneath so that the shadows of the ripples will show on the paper 2) The distance between each shadow line is equal to one wavelength. (Should draw the ripple lines on the paper, perhaps easier to film it then slow mo or pause it). So, measure the distance between the shadow lines that are 10 wavelengths apart, then divide this distance by 10 to find the average wavelength 3) This is a good method for measuring the wavelength of moving waves or small wavelengths 4) Use wavespeed = frequency x wavelength to calculate the speed of the waves (frequency by counting waves that pass in 10 seconds, then divide by 10) The setup is ideal, as you can measure the wavelength without disturbing the waves

Question 26

All waves can be absorbed, transmitted or reflected. True or false?

Answer 26

True

Question 27

When a wave meets a boundary between 2 materials, what 3 things can happen?

Answer 27

1) The wave is ABSORBED by the second material - the wave transfers energy to the material's energy stores. Often, the energy is transferred to a thermal energy store, which leads to heating (how a microwave works) 2) The wave is TRANSMITTED through the second material - the wave carries on travelling through the new material, often leading to refraction. Can be used in communications as well as the lenses of glasses or cameras 3) The wave is reflected - where the incoming ray is neither absorbed or transmitted, but instead sent back away from the second material. How echoes are created