Waves

Question 1

What are the two types of wave?

Answer 1

Transverse and longitudinal

Question 2

What makes a transverse wave?

Answer 2

When the oscillation is perpendicular (90 degrees) to the flow of energy

Question 3

What makes a longitudinal wave?

Answer 3

Whenthe oscillation is parallel to the flow of energy

Question 4

Give some examples of transvers waves

Answer 4

All electromagnetic waves (radio, microwave, IR, visible light, UV, X-rays and gamma) water waves, s-waves, Mexican waves

Question 5

Give some examples of longitudinal waves

Answer 5

Sound, ultrasound and P-waves

Question 6

What do the terms compression a rarefaction mean?

Answer 6

Compression is when a wave squashes the particles together (high pressure) rarefaction is when the particles are stretched apart by the wave (low pressure)

Question 7

What does the term frequency mean and what is its unit?

Answer 7

The number of waves or vibrations per second (measured in hertz)

Question 8

What does the term wavelength mean and what is its unit?

Answer 8

Thedistance between two successive peaks or trough of a wave (measured in meters)

Question 9

How do we calculate wave speed?

Answer 9

Either time how long it take to travel a known distance and divide distance by time, or multiply its frequency by its wavelength

Question 10

What does the term amplitude mean?

Answer 10

The height of the wave from its middle

Question 11

What is the order of the EM spectrum starting with the longest?

Answer 11

Radio microwave IR visible light UV X-rays Gamma

Question 12

Which EM wave has the shortest wavelength?

Answer 12

Gamma

Question 13

Which has the highest frequency?

Answer 13

Gamma

Question 14

What are the uses of radio waves?

Answer 14

Television , car radios

Question 15

What are the uses of microwaves?

Answer 15

Satellite communications, cooking food, WiFi

Question 16

What are the uses of IR?

Answer 16

Toasters , grills, night vision cameras, remote controls

Question 17

What are the uses of visible light?

Answer 17

Fibre optic communication, TV, cameras

Question 18

What are the uses of UV?

Answer 18

Sun tanning, security marker pens, bank notes

Question 19

What are the uses of x -rays and gamma?

Answer 19

Medical imaging and radiotherapy

Question 20

Which EM waves are ionising?

Answer 20

UV, X-rays and gamma

Question 21

What does ionising mean?

Answer 21

The radiation has enough energy to knock electrons out of the orbits around atoms

Question 22

Why is ionising radiation bad for humans?

Answer 22

Ionising radiation can cause cancer

Question 23

Why is UV dangerous for humans?

Answer 23

It can cause skin cancer and damage the eye

Question 24

What type of cancers is associates with X-rays?

Answer 24

Bone cancers

Question 25

How does period and frequency relate to each other?

Answer 25

Frequency is 1 divided by the period (inverse) and likewise period is 1 divided by the frequency

Question 26

How do we measure frequency on a ripple tank?

Answer 26

Either read off the stroboscope or count how many waves are made in 10 seconds and five the answer by 10

Question 27

How do we measure wave speed with a ripple tanks

Answer 27

Either multiple the wavelength by the frequency or time how long the Eve takes to travel the distance of the tank with a stopwatch and measure the length of the ripple tank with a ruler and the divide the distance by the time to find the speed.

Question 28

How do we measure the wavelength of wave on a ripple tank?

Answer 28

With take a photo or use a strobe scope to stop the waves from appearing to move. Then measure the length between 7 or more waves together and divide by the number of waves. ( remember the number of waves will be one less than the number of dark lines) This will be more accurate than measuring just one wave.

Question 29

How can we measure to speed of a wave in air?

Answer 29

Measure a large distance with a trundle wheel and then have someone make a loud sound that is easy to see ( bang two wooden blocks together) at one side and have another person time the delay between seeing and hearing them. Distance divided by time equals speed. You could do this with the sound reflecting of a flat surface like a wall but you need to remember the distance the sound travels will be double the distance to the wall.

Question 30

How does ultrasound imaging and echo location work?

Answer 30

Sound is sent out from a transmitter and the reflections are timed back to the receiver. An image or distance can be found from when different reflections returns.

Question 31

What mathematical number does K represent?

Answer 31

1000

Question 32

What mathematical number does M represent ?

Answer 32

1,000,000

Question 33

What mathematical number does m represent?

Answer 33

0.001

Question 34

How do microwaves heat food?

Answer 34

Microwaves are absorbed by water molecules in the food which then vibrate more heating the food up.