1.5 Waves for Communication and Evidence that the Univers is Expanding

Question 1

Which letter represents the wavelength?

Answer 1

a

Question 2

Which letter represents the amplitude?

Answer 2

b

Question 3

What type of wave is this?

Answer 3

Transverse

Question 4

What type of wave is this?

Answer 4

Longitudinal

Question 5

What type of waves are the electromagnetic waves?

Answer 5

Transverse

Question 6

What type of waves are sound waves?

Answer 6

Longitudinal

Question 7

Which electromagnetic wave is fastest in a vacuum?

Answer 7

They are all the same speed

Question 8

What happens to a wave when it hits an uneven surface?

Answer 8

It reflects at random angles

Question 9

What happens to a wave when it hits an even surface?

Answer 9

It reflects at the same angle

Question 10

What is the law of reflection?

Answer 10

Angle of incidence = Angle of reflection

Question 11

What is refraction?

Answer 11

When a wave crosses a boundary between 2 media and it changes direction because it changes speed

Question 12

Why do waves refract?

Answer 12

Because the different media have different densities causing the wave to slow down or speed up. This changes the direction

Question 13

What is diffraction?

Answer 13

Waves spreading out when they pass through a gap or pass an obstacle

Question 14

What determines the amount of diffraction?

Answer 14

The size of the gap relative to the wavelength of the wave. The narrower the gap/longer the wavelength, the greater diffraction

Question 15

When does maximun diffraction occur?

Answer 15

When the size of the gap is equal to the size of the wavelength

Question 16

What are the electromagnetic waves

Answer 16

• Radio waves
• Micro waves
• Infra red
• Visible light
• Ultra violet
• X-Rays
• Gamma rays

Question 17

Which wave in the electromagnetic spectrum has the smallest wavelength?

Answer 17

Gamma waves

Question 18

Which wave in the electromagnetic spectrum has the highest frequency?

Answer 18

Gamma rays

Question 19

Which waves in the electromagnetic spectrum are used for communication?

Answer 19

• Radio waves
• Microwaves
• Infrared
• Visible light

Question 20

What form of communication are radio waves used for and how?

Answer 20

Television and radio. Long-wave radio waves can be transmitted a long way as they diffract around the Earth. Short-wave radio waves are transmitted a long way as they reflect off the ionosphere.

Question 21

What form of communication are microwaves used for and how?

Answer 21

Satellite communication and mobile phones. Microwaves can pass through the ionosphere. A microwave is sent to a satellite which is then returned to satellite dishes on Earth

Question 22

What form of communication are infrared waves used for and how?

Answer 22

Remote controls and optical fibres. Remote controls send different patters of infrared which can be interpreted to preform different actions. Optical fibres carry data over long distances very quickly.

Question 23

What form of communication is visible light used for and how?

Answer 23

Photography. A lens focuses visible light onto a film or sensor.

Question 24

Can sound waves reflect/refract/diffract?

Answer 24

Reflect and refract

Question 25

What affects the pitch of a sound?

Answer 25

Frequency. Higher frequency, higher pitch

Question 26

What affects the volume of a sound?

Answer 26

Amplitude. Greater amplitude, greater volume

Question 27

Define the Doppler effect

Answer 27

A moving object that is emitting waves will have different waves depending where you are in relation to the object.

If the object is moving towards you, the frequency will be higher and the wavelength will be shorter.

If the object is moving away from you, the frequency will be lower and the wavelength will be longer.

Question 28

What does red-shift show and how?

Answer 28

That galaxies are moving away from us. The light from other galaxies have slightly lower frequencies (they’re shifted to the red end of the spectrum), this shows that they’re moving away from us because the doppler of the doppler effect (objects moving away from us have lower frequencies and higher wavelengths)