The wave equation

Question 1

what is a wave?

Answer 1

a wave is a transfer of energy

Question 2

what is a medium?

Answer 2

a medium is a substance that can ‘carry’ the wave, for example a solid, liquid or gas

Question 3

what happens when a wave travels through a medium?

Answer 3

the particles in the medium might move but they don’t travel with energy

Question 4

wavelength

Answer 4

the distance between two identical points on a wave

Question 5

what is wavelength measured in?

Answer 5

metres

Question 6

what is the symbol for wave length?

Answer 6

λ

Question 7

frequency

Answer 7

how many wavelengths there are per second (number of complete waves per second)

Question 8

does frequency have to be a whole number?

Answer 8

no it does not

Question 9

what is frequency measured in?

Answer 9

Hertz (Hz)

Question 10

amplitude

Answer 10

the maximum displacement of a point on a wave from its equilibrium position (how tall a wave is)

Question 11

what is amplitude measured in?

Answer 11

metres

Question 12

period

Answer 12

the time taken for one full wavelength (how long it takes for one wave to go through a certain point)

Question 13

what is period measured in?

Answer 13

seconds

Question 14

time period

Answer 14

the time taken for 1 whole wave to pass through a fixed point

Question 15

wave speed

Answer 15

the distance a wave travels in one second

Question 16

how do you use a ripple tanks to measure the frequency of water waves?

Answer 16

count the number of waves past a point and measure how long this takes

Question 17

what was the independent variable in the ripple tank PAG?

Answer 17

frequency

Question 18

what was the dependent variable in the ripple tank PAG?

Answer 18

wavelength

Question 19

what were the control variables in the ripple tank PAG?

Answer 19

the amount of water

Question 20

what was the method for the ripple tank PAG?

Answer 20

1. place a ruler in the ripple tank
2. measure the distance between wave peaks, this is the wavelength
3. count how many waves pass a point in 10 seconds, this is the frequency x 10
4. calculate the wave speed
5. repeat for different wave frequencies

Question 21

do you expect the speed of the waves to be the same every time in the ripple tank PAG?

Answer 21

No, because we change the wavespeed

Question 22

why would this practical be different without slow motion?

Answer 22

yes, because it is very hard to measure wavelength and number of waves

Question 23

how would a stroboscope improve the ripple tank PAG?

Answer 23

it produces a flashing light with the same frequency as the waves, the waves appear stationary on the screen and that allows us to measure the wavelength accurately

Question 24

what are two possible sources of error in the ripple tank PAG?

Answer 24

1. couldn’t count number of waves accurately
2. couldn’t measure wavelength accurately

Question 25

what are two ways to improve the ripple tank PAG?

Answer 25

1. take a slow mo video in order to calculate the frequency
2. take a picture/use a stroboscope