EM Waves in Depth

Question 1

electromagnetic wave

Answer 1

oscillating Electric and magnetic waves perpendicular to each other

Question 2

speed of light

Answer 2

3 x 10-8

Question 3

highest frequency

Answer 3

gamma rays

Question 4

lowest frequency

Answer 4

radio waves

Question 5

higher the frequency . . .

Answer 5

higher the energy, lower wavelength

Question 6

microwave uses

Answer 6

cooking food - water molecules absorb energy, satellite communications

Question 7

infrared uses

Answer 7

cooking food, cameras - emit red glow, heaters

Question 8

visible light uses

Answer 8

vision, photography, fibre optics - no lost to sides

Question 9

ultraviolet uses

Answer 9

energy efficient bulbs, fluorescent light - bulb coating absorbs, tan, security marking

Question 10

x-ray uses

Answer 10

medical imaging, photographic plate uses for shadows

Question 11

gamma rays uses

Answer 11

medical treatment, food sterilisation

Question 12

dangers of EM

Answer 12

heating effect, change in nuclei - EM generates over wider range + electrons move, skin cancer, ageing, cancer - ionising

Question 13

why are transmitters tall?

Answer 13

radio waves travel in straight lines

Question 14

shorter wavelength . . .

Answer 14

more information over less range, less spread out

Question 15

carrier wave

Answer 15

wave carrying any type of signal

Question 16

dangers of microwaves

Answer 16

via phones, less dense younger skulls penetrate through affecting brain

Question 17

how are x-rays produced?

Answer 17

particles moving at a high speed are stopped

Question 18

contrast medium use + example

Answer 18

barium, see image more clearly as easy absorption

Question 19

CCD

Answer 19

charge-coupled device, flat panel detector to convert x rays into visible light for image

Question 20

why is a lead plate placed between a patient and tube?

Answer 20

x rays do not reach other parts of body

Question 21

computerised technological x rays disadvantage

Answer 21

exposed to more radiation for longer amount of time

Question 22

by gamma rays killing 99% of bacteria and their waste . . .

Answer 22

food shelf life is increased and food waste is decreased, spread of hospital disease is decreased

Question 23

what emits gamma rays for cancer treatment?

Answer 23

cobalt-60