AS Mock Flashcards KC

Question 1

What are progressive waves?

Answer 1

Wave that transfers energy from one point to another without transferring the medium itself

Question 2

What are examples of progressive waves

Answer 2

Transverse
Longitudinal

Question 3

What are longitudinal waves?

Answer 3

the particles oscillate parallel to the direction of the wave travel (and energy transfer) Longitudinal waves show areas of compressions and rarefactions.

Question 4

What are some examples of longitudinal waves?

Answer 4

Sound waves
Ultrasound waves
P waves

Question 5

What are transverse waves?

Answer 5

where the particles oscillate perpendicular to the direction of the wave travel (and energy transfer)

Question 6

What are some examples of transverse waves?

Answer 6

ripples on the surface of water.
vibrations in a guitar string.
a Mexican wave in a sports stadium.
electromagnetic waves – eg light waves, microwaves, radio waves.
seismic S-waves.

Question 7

Which types of waves polarise?

Answer 7

Transverse waves only

Question 8

What is the relationship between amplitude and intensity?

Answer 8

A^2 directly proportional to I
A=A0 X COS THETA
A = amplitude of light coming through
A0 = amplitude of light that came through the first filter

Question 9

What is Malus’ law?

Answer 9

I=I0 X cos^2 theta

Question 10

When does interference occur?

Answer 10

When waves overlap and their resultant displacement is the sum of the displacement of each wave
This result is based on the principle of superposition

Question 11

When are waves coherent?

Answer 11

Same frequency
Constant phase difference

Question 12

What is coherence?

Answer 12

Points where the 2 waves are in phases, the resultant amplitude is somewhere in between the two extremes
When coherent sound waves are in phase, the sound is larger due to constructive interference

Question 13

Why is coherence important?

Answer 13

Coherence is important in order to produce an observable, or hearable interference pattern

Question 14

What is an example of coherent light source

Answer 14

Laser light

Question 15

What is an example of an incoherent source?

Answer 15

Filament lamp

Question 16

What is constructive interference?

Answer 16

Constructive interference occurs when the maxima of two waves add together (the two waves are in phase), so that the amplitude of the resulting wave is equal to the sum of the individual amplitudes.
when two waves overlap in such a way that they combine to create a larger wave

Question 17

What is destructive interference?

Answer 17

happens when two waves overlap in such a way that they cancel each other out

Question 18

What is path difference?

Answer 18

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

Question 19

What is the condition for constructive interference?

Answer 19

path difference of n lambda (in phase)

Question 20

What is the condition for deconstructive interference?

Answer 20

path difference of (n+1/2) lambda (out of phase)

Question 21

Refractive index equation

Answer 21

n = c/v
c = speed of light in a vacuum
V = speed of light in a material

Question 22

When does refraction occur?

Answer 22

When a wave passes from one transparent medium to another

Question 23

What two things happen when refraction occurs?

Answer 23

Speed of wave changes
Wave will change direction

Question 24

What is snell’s law?

Answer 24

n1 x sin theta1 = n2 x sin theta2
n1 = refractive index
the higher the refractive index, the slower the EM radiation travels through this material compared with its speed in a vacuum

Question 25

What is the critical angle?

Answer 25

Is the angle of incidence in a dense medium such that the angle of refraction in the less dense medium is = 90 degrees

Question 26

What is total internal reflection?

Answer 26

Initially, at an angle smaller than the critical angle, refraction will occur but there will also be a weak reflected ray.
When angle of incidence increases, angle of refraction increases so reflected ray gets stronger
At an angle of incidence greater than the critical angle, no refraction occurs and all of the light will be reflected - TOTAL INTERNAL REFLECTION

Question 27

Critical angle equation

Answer 27

Sin C = n2/n1

Question 28

READ POLARISING AND YOUNG DOUBLE SLIT PAGES

Question 29

What is the benefit of increasing the no of slits

Answer 29

Increases the brightness and sharpness of the maxima and makes it easier to measure an accurate value for the wavelength of light
Maxima are further apart so the angle can be measured with a lower % uncertainty

Question 30

For constructive interference to occur and for a maximum to be produced on the screen there must be a whole no of wavelengths and they must occupy a distance of d sin theta

Answer 30

n lambda = d sin theta
n = order of maximum (order - no of the pattern on either side of the central maximum)
d = separation of the slits
theta = angle that the beam makes with the grating
lambda - wavelength of the incident monochromatic wave

Question 31

READ STANDING WAVES PAGES

Answer 31

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Question 32

Kirchhoff’s 1st law

Answer 32

sum of the current entering a junction in a circuit is = to the sum of the currents leaving the junction
conservation of charge

Question 33

Kirchhoff’s 2nd law

Answer 33

In any closed loop, the sum of the emf is = to the sum of the product of the current and the resistance
conservation of energy

Question 34

Potential divider derivation

Answer 34

Question 35

How does LDR work?

Answer 35

When intensity of light increases, the resistance decreases