Topic THREE - Waves

Question 1

what is the definition of amplitude in progressive waves?

Answer 1

the max displacement from equilibrium

Question 2

what is the definition of wavelength in a progressive wave?

Answer 2

the length of one complete wave

Question 3

what is the definition of displacement in a progressive wave?

Answer 3

distance a particle moves from its equilibrium position

Question 4

what is the definition of a period in a progressive wave?

Answer 4

time taken to complete one wave

Question 5

what is the definition of frequency is a progressive wave?

Answer 5

no. of waves per sec

Question 6

what is the definition of wave speed in a progressive wave?

Answer 6

wavelength/period

Question 7

what is the definition of phase angle in a progressive wave?

Answer 7

the position along the wave

Question 8

when the x-axis on a wave is distance what is the name of the distance between two adjacent points of the wave?

Answer 8

wavelength

Question 9

when the x-axis on a wave is time what is the name of the distance between two adjacent points of the wave?

Answer 9

Time period (T)

Question 10

what is the definition of a longitudinal wave?

Answer 10

the oscillations are parallel to the direction of movement

Question 11

what is compression?

Answer 11

when particles are close together in a longitudinal wave

Question 12

what is the definition of rarefraction?

Answer 12

when particles are spread out in a longitudinal wave

Question 13

how do you find the wavelength in a longitudinal wave?

Answer 13

measure the distance between one compression/rarefraction to the next

Question 14

how do you find the amplitude in a longitudinal wave?

Answer 14

its the max distance a particle moves from its equilibrium point

Question 15

what is the definition of a transverse wave?

Answer 15

ossilations are perpendicular to the direction of movement of the wave

Question 16

what are examples of transverse and longitudinal waves?

Answer 16

transverse - water, EM, Mexican waves

longitudinal - Sound

Question 17

what is polarisation?

Answer 17

process where transverse waves are made to oscillate in one plane only

Question 18

how do you work out phase difference in rads?

Answer 18

2 π d / λ

Question 19

what are the values for something that is completly in phase?

Answer 19

1 cycle = 360° = 2π

Question 20

what are the values for something that is completely out of phase

Answer 20

1/2 cycle = 180° = π

Question 21

what is the definition of path difference?

Answer 21

the difference in distance travelled by 2 waves from their sources to the point where they meet

Question 22

when will there be constructive interference in path difference?

Answer 22

nλ

Question 23

when will there be destructive interference in path difference?

Answer 23

(n + 0.5) λ

Question 24

when are stationary waves formed?

Answer 24

when 2 progressive waves travel in opposite directions and superpose

Question 25

what are the three properties of stationary waves?

Answer 25

- reflects between 2 fixed points - waves have the same amplitude - 2 waves travel in opposite direction

Question 26

what are antinodes?

Answer 26

points of max displacement

Question 27

what are nodes?

Answer 27

points of no displacement

Question 28

what do you get when two waves in phase superpose each other?

Answer 28

constructive interference

Question 29

what do you get when two waves out of phase superpose each other?

Answer 29

destructive interference

Question 30

what is the definition of a coherent wave?

Answer 30

waves with the same λ, same f and a constant phase difference

Question 31

what is the definition of a monochromatic light source

Answer 31

1 λ

Question 32

What is Total internal reflection (TIR) ?

Answer 32

full reflection occurs at the inside boundary of the material (optical fibre)

Question 33

what is the critical angle?

Answer 33

the angle where TIR occurs

Question 34

what is the refractive index of air?

Answer 34

1

Question 35

what is snells law?

Answer 35

n1 x sin θ1 = n2 x sin θ2

Question 36

what is observed when TIR happens?

Answer 36

all light is refracted

Question 37

what are the two rules needed for TIR to happen?

Answer 37

θi > θc | n1 > n2

Question 38

what do you observe in double slit vs single slits?

Answer 38

double - maxima and minima | single - maximum and mininmum

Question 39

what happens at the maxima?

Answer 39

constructive interference (waves are completely in phase)

Question 40

what happens at the minima?

Answer 40

destructive interference (waves are completely out of phase)

Question 41

how do you work out path difference in max + min points?

Answer 41

max : nλ | min: (n + 0.5) λ

Question 42

how do you find the max order?

Answer 42

d / λ | rounded down

Question 43

how do you work out line spacing?

Answer 43

1 / lines per m

Question 44

how do you derive d sinθ = nλ ?

Answer 44

SOHCAHTOA sin θ = λ / d d sin θ = λ for the nth order: d sin θ = λn