Chapter 12 - Using Waves Flashcards

1
Q

How do waves at one end of the EM spectrum differ from waves at the other end? (2 marks)

A
  • One end is high frequency, short wavelength - Other end is low frequency, long wavelength
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2
Q

What 4 properties do all waves have? (4 marks)

A
  • All transfer energy - All transverse waves - Travel at the speed of light in a vacuum - All can be reflected, refracted and diffracted
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3
Q

Radio waves have the ……. wavelength in the EM spectrum (1 mark)

A

Longest, meaning low frequency

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4
Q

How are radio waves used in TV and FM radio (3 marks)

A
  • Given out by a transmitter - As they cross an aerial, they are detected and info they carry can be received - TV and FM radio use radio waves with short wavelengths to carry their signals
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5
Q

What are the sources and detectors for radio waves (2 marks)

A

Sources - Radio and TV transmitters Detectors - Radio and TV aerials

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6
Q

Microwaves have a …. wavelength and a … frequency (2 marks)

A
  • Long - Low
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7
Q

How do microwaves heat food (5 marks)

A
  • Special electrical circuits produce microwaves - Metal guides direct microwaves towards a rotating reflector - This reflector sends microwaves in all directions - Microwaves are reflected from metal casing - Food absorbs microwaves and becomes hot
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8
Q

Two uses of microwaves (4 marks)

A
  • Cooking : microwaves are used as food absorbs microwaves and becomes hot - Phones : messages sent to and from mobile phones are also carried by microwaves
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9
Q

What are the sources and detectors for microwaves (2 marks)

A

Sources - microwave transmitters and ovens Detectors - microwave receivers

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10
Q

Describe two differences between X-rays and visible light (2 marks)

A
  • X-rays have shorter wavelength - X-rays have higher frequency
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11
Q

State the name of the type of wave that includes X-rays and visible light

A

electromagnetic

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12
Q

Which of the following is NOT a medical use of X-rays? A - Pre-natal scanning B - CT scans C - Killing Cancer Cells

A

A - Pre-natal scanning

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13
Q

True or false? X-rays can be used to diagnose dental problems.

A

True

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14
Q

Are X-rays absorbed or transmitted by metal?

A

absorbed

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15
Q

True or false? X-rays can be used to break up kidney stones.

A

False

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16
Q

EM SPECTRUM ACRONYM

A

Raging

Martians

Invaded

Venus

Using

X-ray

Guns

17
Q

A microwave cooker is often said to ‘cook the food from the inside

Explain whether this statement is true by describing how energy is transferred to heat up all of the potato [3 marks]

A
  • Microwaves are electromagnetic waves
  • They cause water molecules to vibrate more / heat water
  • Conduction through the rest of the potato
18
Q
A
  • Electromagnetic induction
  • Coil creates magnetic field around it
  • Which cuts through the metal pan
  • Inducing a voltage in the pan;
  • Causing a current in the pan
  • Current makes the pan get hot
  • Which heats the water by conduction
  • Water convects energy to potato;
19
Q

Suggest a property of radio waves that makes them suitable for use in communication [1 mark]

A

Can travel long distances

20
Q

Describe a possible harmful effect on people of microwaves [1 marks]

A

heating

21
Q

Describe a use of ultraviolet rays [1 marks]

A

kill bacteria

22
Q

Possible harmful effect on people of ultraviolet rays [1 marks]

A

skin cancer

23
Q

Explain what is meant by a digital signal [2 marks]

A
  • Signal has two values

-

24
Q

Suggest two ways that this signal could be made to carry more information [2 marks]

A
  • Increased frequency of wave
  • using increased bandwidth;
25
Q
A

C

26
Q
A

A

27
Q
A

C

28
Q

Gamma radiation is used in hospitals even though it can be dangerous. Describe one use of gamma radiation in hospitals.

(2)

A
  • sterilising medical equipment; gamma kills bacteria;
  • treating cancer/mutates cancer cells; radiotherapy/focused gamma rays;
  • detecting cancer; PET scanner/(radioactive) tracers/gamma camera;
29
Q

Explain the risks to patients and doctors of using gamma radiation. (2)

A
  • increased risk of cancer/mutation of cells damage to neighbouring/good/healthy cells
  • radiation is ionising gamma has high/highest energy
  • patient is only exposed for a short period of time doctor has continual (low level) exposure
30
Q

State one way of reducing the risks to a doctor who uses gamma radiation. (1)

A
  • (use for a) limited time
  • idea of working at a distance/in another room