P5.2 - Electromagnetic Fields Flashcards Preview

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Flashcards in P5.2 - Electromagnetic Fields Deck (24)
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1
Q

what angle do electromagnetic fields oscillate at (relative to the direction of the wave)?

A

90 degrees

2
Q

What speed do electromagnetic waves travel at? (and what is this the same as)

A

3 x 10 ^8 m/s

  • same as speed of light
3
Q

name two sources of electromagnetic waves

A

microwave, sun

4
Q

what is the equation to calculate the frequency of a wave?

and what is the unit

A

wave speed
—————
wavelength

(Hz)

5
Q

State 2 uses of radio waves

A
  • TV signals
  • FM and AM radio broadcasts
6
Q

State uses of micro waves

A
  • to heat up food in the microwave
  • communication (WiFi, mobile phones, satellites)
7
Q

State uses of infrared waves

A
  • Remote controls
  • fibre optic communication
  • thermal imaging
8
Q

State a use of visible light

A
  • morse code in ships
  • for photography
9
Q

State uses of ultraviolet waves (just remember 2)

A
  • to detect forged bank notes
  • fluorescent bulbs
  • sterilises water (kills bacteria)
  • can be used for suntans
10
Q

State uses of X-ray

A
  • used for X-rays
  • can kill skin cancer or other skin cells
  • used for airport security
11
Q

State uses of gamma rays

A
  • can kill cancer cells
  • can sterilise medical instruments
12
Q

Are ultraviolet rays dangerous, and if so why?

A

YES

  • can damage DNA in cells (grow very rapidly and cause skin cancer)
  • if eyes exposed, cataracts can develop (make corneas cloudy)
13
Q

Are X-rays dangerous and if so why?

A
  • can damage cells

- can cause cancer

14
Q

Are gamma rays dangerous and if so why?

A
  • can damage cells in body

- leads to cancer

15
Q

Name the group of the electromagnetic spectrum used to kill cancer cells.

A

gamma rays or x-rays

16
Q

Describe the nature of an electromagnetic wave

A
  • oscillate at a right angle/90 degrees to the wave’s direction.
  • wave pointing up = magnetic field
  • wave pointing sideways = electric field
  • it is a transverse wave
17
Q

Describe why bones show up white on the X-ray film

A
  • Bones absorb X-rays
18
Q

When radiographers operate X-ray machines, they stand behind lead screens. The screens absorb X-rays and prevent the operators from being repeatedly exposed to radiation.
Explain why this is a necessary precaution.

A

X-rays / gamma rays can damage DNA / are harmful to cells

19
Q

what kind of waves are electromagnetic waves?

A

transverse waves

20
Q

what is the relationship between frequency and wavelength across the electromagnetic spectrum

A

the greater the frequency, the smaller the wavelength

21
Q

what are our eyes sensitive to?

A

only visible light, not absorbed by the atmosphere

22
Q

can electromagnet waves travel through a vacuum?

and why

A

yes!

  • as they are emitted from the sun and travel to the earth through SPACE
  • remember space is a vacuum
23
Q

describe the difference between a longitudinal and transverse wave

A
  • in a longitudinal wave, oscillations occur parallel to the direction of energy transfer
  • in a transverse wave, oscillations occur perpendicular to the direction of energy transfer
24
Q

mnemonic to remember electromagnetic spectrum

A

Reptiles
Make
Interesting
Voices
Under
X-treme
Gold