T6 electromagnetic waves Flashcards

1
Q

what type of spectrum do electromagnetic waves form

A

continuous spectrum

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2
Q

what type of spectrum do electromagnetic waves form

A

continuous spectrum

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3
Q

order the types of electromagnetic radiation from lowest to highest frequency

A

radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays

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4
Q

how do the speeds of EM radiation differ in a vacuum and in air

A

electromagnetic waves all travel at the same speed in a vacuum and in air

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5
Q

what property of waves in different mediums causes refraction

A
  • velocity

- wave speed is slower in denser materials, causing refraction

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6
Q

in which direction do waves refract when entering a denser medium

A
  • bend towards the normal

- angle of refraction is less than the angle of incidence

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7
Q

what type of waves can be produced by oscillations in an electrical circuit

A

radio waves

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8
Q

how can radio waves create an alternating current in a circuit

A

when radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves

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9
Q

where do gamma rays originate from

A

changes in the nuclei of atoms

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10
Q

what health effects can ultraviolet waves cause

A
  • can cause the skin to age prematurely

- can increase the risk of developing skin cancer

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11
Q

what health effects can X-rays and gamma rays cause

A
  • ionising radiation so can cause mutations in genes

- can lead to increased risk of developing various cancers

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12
Q

give 3 practical uses for infrared radiation

A
  1. electrical heaters
  2. cooking food
  3. infrared cameras
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13
Q

give 2 practical uses for microwave radiation

A

cooking food

satellite communications

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14
Q

give 2 practical uses for radio waves

A

television transmission

radio transmission

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15
Q

what wave phenomenon is used by lenses to form an image

A

refraction

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16
Q

how does a convex lens form an image

A

parallel rays are refracted and brought together at a point known as the principal focus

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17
Q

what is meant by the focal length of a lens

A

distance from the lens to the principle focus

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18
Q

what is the difference between the image produced by a convex and a concave lens

A
  • convex lenses can produce real or virtual images

- concave lenses can only produce virtual images

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19
Q

why does magnification not have a unit

A
  • it’s the ratio between image height and object height

- ratios don’t require units

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20
Q

symbol used to represent a convex lens in a ray diagram

A
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21
Q

symbol used to represent a concave lens in a ray diagram

A

>

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22
Q

what determines the colour of visible light waves

A

wavelength and frequency of the light waves

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23
Q

what colour of visible light has the highest frequency

A

blue

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24
Q

what colour of visible light has the largest wavelength

A

red

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25
Q

what is meant by the term specular reflection

A

reflection from a smooth surface in a single direction

26
Q

what is meant by the term diffuse reflection

A

reflection from a rough surface which causes scattering

27
Q

how does a red colour filter work

A
  • a red filter absorbs all wavelengths of light other than those in the red range of the spectrum
  • this means only red light passes through the filter
28
Q

what determines the colour of an opaque object

A
  • different objects reflect different wavelengths of light by different amounts
  • the wavelengths that are most strongly reflected determine the colour
29
Q

what happens to the wavelengths of light that aren’t reflected by an opaque object

A

any wavelengths that aren’t reflected are absorbed by the object

30
Q

what colour does an object appear if all wavelengths are reflected by equal amounts

A

white

31
Q

what colour does an object appear if all wavelengths are abosorbed

A

black

32
Q

order the types of electromagnetic radiation from lowest to highest frequency

A

radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, gamma rays

33
Q

how do the speeds of EM radiation differ in a vacuum and in air

A

electromagnetic waves all travel at the same speed in a vacuum and in air

34
Q

what property of waves in different mediums causes refraction

A
  • velocity

- wave speed is slower in denser materials, causing refraction

35
Q

in which direction do waves refract when entering a denser medium

A
  • bend towards the normal

- angle of refraction is less than the angle of incidence

36
Q

what type of waves can be produced by oscillations in an electrical circuit

A

radio waves

37
Q

how can radio waves create an alternating current in a circuit

A

when radio waves are absorbed, they can induce oscillations in a circuit with the same frequency as the waves themselves

38
Q

where do gamma rays originate from

A

changes in the nuclei of atoms

39
Q

what health effects can ultraviolet waves cause

A
  • can cause the skin to age prematurely

- can increase the risk of developing skin cancer

40
Q

what health effects can X-rays and gamma rays cause

A
  • ionising radiation so can cause mutations in genes

- can lead to increased risk of developing various cancers

41
Q

give 3 practical uses for infrared radiation

A
  1. electrical heaters
  2. cooking food
  3. infrared cameras
42
Q

give 2 practical uses for microwave radiation

A

cooking food

satellite communications

43
Q

give 2 practical uses for radio waves

A

television transmission

radio transmission

44
Q

what wave phenomenon is used by lenses to form an image

A

refraction

45
Q

how does a convex lens form an image

A

parallel rays are refracted and brought together at a point known as the principal focus

46
Q

what is meant by the focal length of a lens

A

distance from the lens to the principle focus

47
Q

what is the difference between the image produced by a convex and a concave lens

A
  • convex lenses can produce real or virtual images

- concave lenses can only produce virtual images

48
Q

why does magnification not have a unit

A
  • it’s the ratio between image height and object height

- ratios don’t require units

49
Q

symbol used to represent a convex lens in a ray diagram

A
50
Q

symbol used to represent a concave lens in a ray diagram

A

>

51
Q

what determines the colour of visible light waves

A

wavelength and frequency of the light waves

52
Q

what colour of visible light has the highest frequency

A

blue

53
Q

what colour of visible light has the largest wavelength

A

red

54
Q

what is meant by the term specular reflection

A

reflection from a smooth surface in a single direction

55
Q

what is meant by the term diffuse reflection

A

reflection from a rough surface which causes scattering

56
Q

how does a red colour filter work

A
  • a red filter absorbs all wavelengths of light other than those in the red range of the spectrum
  • this means only red light passes through the filter
57
Q

what determines the colour of an opaque object

A
  • different objects reflect different wavelengths of light by different amounts
  • the wavelengths that are most strongly reflected determine the colour
58
Q

what happens to the wavelengths of light that aren’t reflected by an opaque object

A

any wavelengths that aren’t reflected are absorbed by the object

59
Q

what colour does an object appear if all wavelengths are reflected by equal amounts

A

white

60
Q

what colour does an object appear if all wavelengths are abosorbed

A

black