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HDSO Crave the Wave > 6.1, 6.2 and 6.3 The Electromagnetic Spectrum/Light, Infrared, Microwaves and Radio Waves/Communications > Flashcards

6.1, 6.2 and 6.3 The Electromagnetic Spectrum/Light, Infrared, Microwaves and Radio Waves/Communications Flashcards

1
Q

What do electromagnetic waves do?

A

Transfer energy from one place to another

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2
Q

What does the amount of energy that electromagnetic waves transfer depend on?

A

The wavelength of the waves

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3
Q

What is the order of the electromagnetic spectrum?

A 
Radio waves 
Micro waves 
Infrared radiation 
Visible light 
Ultraviolet lights
X Ray 
Gamma ray
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4
Q

How fast do all electromagnetic waves travel?

A

300 million m/s

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5
Q

Describe the similarities and differences of the EM waves

A

Similarities:
Same wave speed
All travel through a vacuum

Differences:
Different wave lengths
Different frequencies

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6
Q

How do we group the EM waves?

A

According to their wavelength

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7
Q

Which type of rays have the shortest wavelength?

A

Gamma rays

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8
Q

Which type of EM waves have the highest frequency?

A

Gamma rays

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9
Q

What is the average wavelength of a gamma ray?

A

10 to the power of -15 m

Or

0.000000000000001

(14 0’s)

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10
Q

Which type of EM waves have the longest wavelength?

A

Radio waves

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11
Q

What type of EM waves have the lowest frequency?

A

Radio waves

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12
Q

What is the average wave length of a radio wave?

A

10,000m

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13
Q

What is the relationship between the frequency of an EM wave and the amount of energy it transfers?

A

The higher the frequency, the more energy it transfers

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14
Q

Why are the wavelengths and frequencies at the boundaries of the different EM waves approximate?

A

The different parts of the spectrum are not precisely defined

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15
Q

How do different surfaces react to the different wavelengths of the EM waves?

A

Different wavelengths of EM radiation are reflected, absorbed or transmitted differently by different substances and types of surface

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16
Q

Which part of the EM spectrum transfers the most energy?

A

Gamma rays

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17
Q

What are electromagnetic waves?

A

Electric and magnetic disturbances

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18
Q

Where can we emit radio waves from?

A

An alternating voltage applied to an aerial emits radio waves with the same frequency as the alternating voltage. When the waves are received, they create an alternating current in the aerial with the same frequency as the radiation received

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19
Q

Name 3 uses of radio waves

A
  • TV
  • radio
  • mobile phone
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20
Q

Name a danger of radio waves used in mobile phones

A

•radiation on the phone can cause damage to our brains

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21
Q

What else gives off radio waves naturally?

A

Stars and lightning

22
Q

What can the frequencies of radio waves range between?

A

300,000Hz to 3 billionHz

23
Q

Where can micro waves be emitted from?

A

Satellites and pass through the atmosphere

24
Q

Name 2 uses of micro waves

A
  • satellite TV

* mobile phones

25
Q

Name a danger of micro waves used in mobile phones

A

Radiation on phone could cause damage to our brains

26
Q

Which waves spread out more: radio or micro?

A

Radio waves

27
Q

Where is infrared radiation emitted?

A

All objects emit infrared radiation

28
Q

Name 3 uses of infrared radiation

A
  • optical fibres
  • remote controls
  • infrared scanners/cameras
29
Q

Name a danger of infrared radiation

A

•absorbed by the skin so can be dangerous to skin cells if they are heated too much and can be destroyed

30
Q

What is the relationship between the heat of an object and the amount of infrared radiation it emits?

A

The hotter the object is, the more infrared radiation it emits

31
Q

Name 2 sources of visible light

A
  • the sun

* ordinary lamps

32
Q

Name two uses of visible light

A
  • lamps

* light bulbs

33
Q

Name 2 dangers of visible light

A
  • sun can cause blindness

* sun burn can cause cancer

34
Q

Where is ultraviolet radiation emitted from?

A

Stars

35
Q

Name 3 uses of ultraviolet radiation

A
  • to check bank notes
  • suntan
  • nail salon
36
Q

Name 2 dangers of ultraviolet radiation

A
  • sun burn

* skin cancer

37
Q

Name 2 sources of x rays and gamma rays

A
  • stars

* X-Ray machines

38
Q

Name 2 uses of X-rays and gamma rays

A
  • airport security

* hospitals

39
Q

What EM waves are the most dangerous and why?

A

Gamma rays because they have the highest frequency

40
Q

Name a danger of X-rays and gamma rays

A

•causes cancer

41
Q

What do we see the different wavelengths of visible light as?

A

Different colours

42
Q

Which colour has the lowest wavelength?

A

Violet

43
Q

Which colour has the biggest wavelength?

A

Red

44
Q

Why is micro wave and radio wave radiation dangerous for us?

A

They penetrate our skin and are absorbed by body tissue, this can heat your internal organs and damage them

45
Q

What is the radio wave and microwave spectrum split into?

A

Different bands, decided by the different communication purposes

46
Q

What does a shorter wavelength mean for the amount of information it carries, their range and the amount they spread out?

A

The shorter the wavelength
•the more information they carry
•the shorter their range
•the less they spread out

47
Q

What type of EM wave lets your phone transfer information to a local mobile phone mast?

A

Micro waves

48
Q

What are optical fibres and what are they used for?

A

Very thin glass fibres used to transmit signals carried by visible light or infrared radiation

49
Q

How does a signal travel down the optical fibre?

A

Total internal reflection

50
Q

Why are optical fibres useful in communications?

A

They carry much more information and are more secure than micro waves as they use visible light and infrared which both have shorter wavelengths

HDSO Crave the Wave (8 decks)

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