waves

Question 1

What is a transverse wave ?

Answer 1

Particle oscillation is perpendicular to the direction of energy transfer

Question 2

What is a longitudinal wave ?

Answer 2

Particle oscillation is in the same direction as energy transfer

Question 3

What is a standing/stationary wave ?

Answer 3

• 2 waves from fixed points creating a singular wave

Question 4

What is a node ?

Answer 4

Points on a stationary wave that have no displacement

Question 5

What is an antinode ?

Answer 5

Points on a stationary wave that have maximum displacement

Question 6

What are the criteria for a stationary wave to form ?

Answer 6

• the same frequency
• similar amplitudes
• travelling in opposite directions

Question 7

What happens if polarised light passes through a second polaroid filter at a different angle ?

Answer 7

No light passes through

Question 8

What is an example of polarised light ?

Answer 8

3D film glasses -> enhances the viewing experience

Question 9

How do 3D film glasses work ?

Answer 9

Each glass lens is 90° to the other, each eye sees a different image

Question 10

What is constructive interference?

Answer 10

When a peak meets a peak, it creates a peak twice as big

Question 11

What is destructive interference?

Answer 11

When a peak meets a trough, they create a flat surface

Question 12

What is the first harmonic ?

Answer 12

When a standing wave creates half a wavelength

Question 13

What does the μ stand for in the equation for the first harmonic ?

Answer 13

Mass in 1 metre

Question 14

What is refraction ?

Answer 14

Bending of a wave when it changes mediums

Question 15

What is the normal ?

Answer 15

Line at 90° to the boundary between 2 mediums

Question 16

What is the angle of incident ?

Answer 16

Angle between the light coming in and the normal

Question 17

What is the angle of refraction ?

Answer 17

Angle between the refracted light and the normal

Question 18

How to find the percentage uncertainty?

Answer 18

( uncertainty / value ) x 100

Question 19

What is the refractive index of air ?

Answer 19

1.0

Question 20

What happens to wavelength as you go further down the rainbow ?

Answer 20

it gets shorter
🟥 🟧 🟨 🟩 🟦 🟪
longest ———————shortest

Question 21

What is the critical angle ?

Answer 21

Where the angle of refraction is 90°

Question 22

What happens when the critical angle is more than angle of incidence ?

Answer 22

Refraction
small reflection

Question 23

What happens when the critical angle is equal to the angle of incidence ?

Answer 23

Refraction at 90°
small reflection

Question 24

What happens when the critical angle is less than angle of incidence ?

Answer 24

Total internal reflection, all light reflected

Question 25

What is the use of the cladding in an optic fibre ?

Answer 25

• stop dispersion
• protect the core (and light leakage)

Question 26

What is light dispersion ?

Answer 26

Light of different colours/speed arrive at different times
Overcome by using monochromatic light

Question 27

What is multimode dispersion ?

Answer 27

Light at different angles arrives at different times
Reduced by increasing refractive index (and θc)

Question 28

When are sources coherent

Answer 28

Constant phase difference between them

Question 29

What is a laser ?

Answer 29

Intense beam of monochromatic light

Question 30

What makes light monochromatic ?

Answer 30

Single λ
Single frequency
Single colour

Question 31

What are the dangers of laser light and precautions to be taken ?

Answer 31

Damage to eyes (intense energy at one point) :
- point at wall/floor and avoid reflective surfaces

Question 32

What does an intensity-distance graph look like ?

Answer 32

Wave graph - each oscillation the peak gets smaller but same width apart

Question 33

What happens in the double slit experiment ?

Answer 33

Light goes through a double slit and fringes are made from the light on screen

Question 34

when does W = λD/s not work ?

Answer 34

When the angle between paths is big/D is not a lot bigger than s

Question 35

What is diffraction ?

Answer 35

Bending of waves around an object

Question 36

What happens in the single slit experiment ?

Answer 36

When using coherent light through a slit the light interferes with other light and creates fringes

Question 37

What is diffraction grating ?

Answer 37

Sending light through many slits at once