P6: EM SPECTRUM

Question 1

The electromagnetic spectrum

Answer 1

-radio waves
-microwaves
-infrared
-visible light
-ultraviolet
-x-rays
-gamma rays

Question 2

What are the properties of EM waves?

Answer 2

-transverse waves
-can travel through a vacuum
-travel at 3x10^8 m/s through a vacuum

Question 3

What are the properties of waves at the top of the EM spectrum?

Answer 3

-low energy
-long wavelength
-low freq

Question 4

What are the properties of waves at the bottom of the EM spectrum?

Answer 4

-high energy
-short wavelength
-high freq

Question 5

Radiowaves:
-how are they produced?
-uses

Answer 5

-produced by oscillations in electrical circuits
-when TV antennae detect radio waves an alternating current is produced at the same freq as the radio waves
USES:
-communication

Question 6

microwaves:
-uses

Answer 6

USES:
-cooking food (absorbed by water molecules in the food causing them to vibrate which heats the food up)
-satellite transmission

Question 7

Infrared:
-how is it produced?
-uses
-dangers

Answer 7

-all objects emit infrared radiation
-the hotter the object the more infrared radiation it emits
USES:
-IR heaters
-IR cameras
-can detect hot spots which can indicate cancer
-TV remote controls
DANGERS
-can cause burns

Question 8

Visible light:
-how is it produced?
-uses
-dangers

Answer 8

-when electrons fall from a higher energy level to a lower energy level visible light photons are emitted
USES:
-photography
-transmit light and info through the optic cables
DANGERS:
-blindness
-eye damage

Question 9

UV:
-uses
-dangers

Answer 9

USES:
-tanning
-fluorescent substances used in energy efficient lamps (substance absorbs UV light then re-emits it as visible light)
DANGERS:
-increased risk of skin cancer
-can cause skin to age prematurely

Question 10

X-rays:
-uses
-dangers

Answer 10

USES:
-used to take images of bones
-airport security
DANGERS:
-ionising so can cause cell mutations and lead to cancer

Question 11

Gamma rays:
-how are they produced?
-uses
-dangers

Answer 11

-unstable isotopes can decay by emitting gamma radiation
USES:
-kill cancer cells
-kill harmful bacteria
-sterilising surgical equipment
-medical imaging
DANGERS:
-ionising so can cause cell mutations and lead to cancer