Electromagnetic Spectrum

Question 1

what is a wave?

Answer 1

Disturbance in any medium which transports energy from one place to another without causing any permanent damage in the medium itself

Question 2

what do waves transport?

Answer 2

energy

Question 3

how do waves transport energy?

Answer 3

by repeating patterns of vibrations

Question 4

what are the two types of waves?

Answer 4

longitudinal
transverse

Question 5

what is a longitudinal wave?

Answer 5

vibrations are parallel to the direction of wave travel. E.g. sound

Question 6

what is a transverse wave?

Answer 6

wave goes up and down, perpendicular to direction of wave. E.g. water waves, electromagnetic radiation

Question 7

what is wavelength?

Answer 7

length of a complete wave cycle
- Trough to trough. Peak to peak

Question 8

units of wavelength

Answer 8

metres (m)

Question 9

what is speed?

Answer 9

distance travelled per unit of time

Question 10

units of speed

Answer 10

m/s or ms-1

Question 11

speed formula

Answer 11

Speed = distance/time

Question 12

what is amplitude?

Answer 12

how high wave gets from mean level

Question 13

what is frequency?

Answer 13

number of wavelengths that occur per unit of time

Question 14

units of frequency

Answer 14

Hertz (Hz)

Question 15

frequency formula

Answer 15

Frequency = 1/time

Question 16

what is period?

Answer 16

time to go through one complete cycle

Question 17

units of period

Answer 17

seconds (s)

Question 18

velocity formula in relation to waves

Answer 18

Velocity = frequency x wavelength

Question 19

what happens when you increase frequency?

Answer 19

increase speed wave goes up and down, wavelength gets shorter

Question 20

how is the relationship between wavelength and frequency?

Answer 20

inverse

Question 21

how is the relationship between wavelength and frequency inverse?

Answer 21

because
- Lower frequency = longer wavelength
- Higher frequency = shorter wavelength

Question 22

what does ionising radiation mean?

Answer 22

Ionising radiation can ionise an atom. Has enough energy to overcome binding energy and eject electron from the atom.

Question 23

examples of ionising radiation

Answer 23

X-rays, gamma-rays, high energy UV

Question 24

what does non-ionising radiation mean?

Answer 24

has insufficient energy to ionise an atom

Question 25

examples of non-ionising radiation

Answer 25

Low-energy ultraviolet, visible, infrared, microwaves

Question 26

properties of electromagnetic radiation

Answer 26

- can travel through a vacuum - comprised of a combo of electric and magnetic fields - all travel at same speed - travel in a straight line

Question 27

what type of waves are electromagnetic radiation?

Answer 27

transverse

Question 28

why is electromagnetic radiation being able to travel through a vacuum important?

Answer 28

important for x-ray tube as otherwise this wouldn’t work

Question 29

how do x-rays originate?

Answer 29

through interactions between electrons and atoms

Question 30

what is EMR the interaction of

Answer 30

electric and magnetic fields travelling at c (speed of light)

Question 31

what properties does a wave with higher frequency have?

Answer 31

higher energy and more ionising

Question 32

energy equation

Answer 32

E = hf E - energy h - Planck's constant f - frequency of the photon (Hz)

Question 33

what is the measure of energy?

Answer 33

Electron volts (eV)

Question 34

what is special about x-rays and gamma rays?

Answer 34

they have characteristics of both waves and particles

Question 35

how can EMR exist as a particle of energy?

Answer 35

as a photon

Question 36

what is quanta?

Answer 36

Individual packets of energy

Question 37

what is the mass and energy of a particle?

Answer 37

zero mass and zero energy

Question 38

how are photons different to electrons?

Answer 38

photons have 0 AMU, travel at speed of light and have no mass

Question 39

what is intensity?

Answer 39

the amount of energy flowing per unit of time per unit area

Question 40

intensity formula

Answer 40

Intensity = power/area

Question 41

intensity units

Answer 41

w/m2 watts per metre squared

Question 42

what is inverse square law?

Answer 42

As you move further from light source, the intensity of light decreases Intensity of light is inversely proportional to the distance squared

Question 43

inverse square law formula

Answer 43

Intensity = 1/distance2

Question 44

what happens when you get 2m further away from x-ray source?

Answer 44

get 1/4 of dose

Question 45

what happens when you get closer to x-ray source?

Answer 45

get more dose