Chapter 11 - Waves

Question 1

wave equation

Answer 1

Velocity = frequency * wavelength

Question 2

what is displacement

Answer 2

Distance and direction of a vibrating particle or a point in field from the equilibrium position

Question 3

key thing to remember about waves?

Answer 3

The particle doesn’t move through the wave. The wave moves through the particles. All the particles do is vibrate and pass on the energy to the particles next to it.

Question 4

what is wavelength

Answer 4

It is the distance between 2 adjacent vibrating particles or points on a field, vibrating (in phase) with the same velocity and displacement

Question 5

what is a period

Answer 5

the time taken for one complete cycle to pass a fixed point

Question 6

what is frequency

Answer 6

the number of cycles passing a fixed point per second

Question 7

what is optical density

Answer 7

this is only for EM waves
the higher the density, the higher the speed of the wave.
Essentially, it is the absorbance of a substance.
It is the ratio of the transmitted light through that substance to the incident light.

Question 8

what changes in a wave

Answer 8

The speed is a fundamental property that changes when crossing between media, leading to a change in wavelength but NEVER FREQUENCY. In the same medium, the speed remains constant.

Question 9

what is 1 radian

Answer 9

the angle subtended at a circle so you can travel the distance ‘radius’ from point A to point B on the circumference

Question 10

what is 2π

Answer 10

360 degrees

Question 11

what is π

Answer 11

180 degrees

Question 12

what is the phase of a point

Answer 12

fraction of a cycle that has been completed since the start of the cycle

Question 13

what is the phase difference (φ)

Answer 13

The difference in the phase between 2 points. The particles or points can be along the same wave or different waves.

Question 14

what is 1 complete wave

Answer 14

2π

Question 15

equation for phase

Answer 15

x/y * 2π

Question 16

equation for phase difference on the same wave

Answer 16

d/x *2π (d= distance)

Question 17

phase difference between 2 DIFFERENT waves

Answer 17

at a given point in space and time, the difference between the current phases of each wave.

Question 18

equation for phase difference between 2 DIFFERENT waves

Answer 18

Current phase in wave 1 - Current phase in wave 2

Question 19

what do 2 particles need to have to be considered to be ‘in phase’

Answer 19

the same velocity and frequency

their phase difference must be an integer of 2π`

Question 20

what is antiphase

Answer 20

if the phase difference is an odd integer of π

Question 21

if a particle is at maximum displacement, what is its velocity?

Answer 21

negative because after being at the top, it will go down, which is negative.

Question 22

explain what is similar and different about two particles, one at the maximum displacement and the other at the minimum displacement

Answer 22

The distance from equilibrium position is equal, which means they are equal in magnitude, but they have different velocities, because one particle is looking to move up and the other is looking to move back down

Question 23

what is a progressive wave

Answer 23

an oscillation that travels through matter and transfers energy from one place to another, without transferring matter.

Question 24

how can you find the period of a wave

Answer 24

p = 1/ frequency

also it is equal to the wavelength on a distance- time graph.

Question 25

what is amplitude

Answer 25

the maximum displacement by a wave motion.