Waves and Photons

Question 1

What does ‘out of phase’ mean?

Answer 1

Where 2 waves have different multiples of the wavelength

Question 2

What does ‘in phase’ mean?

Answer 2

Where 2 waves have the same a multiple of the wavelength

Question 3

What is the equation for a wave that is in phase?

Answer 3

N(lander)

Question 4

What does N stand for in the equations?

Answer 4

Each full wave

Question 5

What is path difference?

Answer 5

The distance between the lengths the waves take

Question 6

What is the principle of superposition?

Answer 6

Where two or more waves meet, the sum of the vector of displacements that the individual waves would cause at a point

Question 7

What is constructive superposition?

Answer 7

Where two or more waves are in phase of each other or have a radian of 0 degrees so will arrive in phase

Question 8

What are coherent waves?

Answer 8

Waves that have the same frequency and maintain a constant phase relationship

Question 9

What is a destructive wave?

Answer 9

Two waves that are of equal frequency but opposite phase arrive at a point

Question 10

What is a wave front?

Answer 10

A line that connects all the waves in a line

Question 11

How do you work out phase difference?

Answer 11

Find the path difference
Divide that by the wavelength
x the answer by 2pirad (because it’s one full wave)
that would be it’s total out of sync or in sync

Question 12

What is the thin lens equation?

Answer 12

1/U + 1/V - 1/F

Question 13

What does the U stand for in the thin lens equation?

Answer 13

Distance from the object to the lens

Question 14

What does the V stand for in the thin lens equation?

Answer 14

Distance from the lens to the image

Question 15

What does the F stand for in the thin lens equation?

Answer 15

Distance from the lens to the focal point

Question 16

With concave lenses, what must always be true?

Answer 16

The lens will produce a virtual and upright image

Question 17

What is the difference between a concave and convex lens?

Answer 17

A convex lens you can project the image onto a screen

Concave lens is a virtual image where the lines would appear to meet

Question 18

What does Huygens construction describe?

Answer 18

A wave forms at a wavefront and has a spherical shape and travels at the same speed and wavelength

Question 19

What is the wavelength of the fundamental harmonic

Answer 19

2L

Question 20

Why does a pencil look bent in water?

Answer 20

The water is more dense than the air so the image doesn’t form as fast so appears to bend round the image

Question 21

What is the definition of incident?

Answer 21

Where the ray first travels from onto an object

Question 22

Define Principal axis

Answer 22

The middle axis which can’t always be seen. Centre of the lens and perpendicular to it

Question 23

Define the normal

Answer 23

Line perpendicular to the boundary

Question 24

What is a focal point?

Answer 24

Where Parallel rays meet at a point`

Question 25

What is focal length?

Answer 25

Distance between the lens and focal point

Question 26

What is the critical angle?

Answer 26

The angle at which refraction doesn't take place and instead internal reflection does

Question 27

What does phase mean?

Answer 27

A point in the wave cycle

Question 28

Define a transverse wave

Answer 28

A wave that oscillates perpendicular to the direction of propagation/ energy transfer

Question 29

Define a longitudinal wave

Answer 29

A wave that oscillates parallel to the direction of energy transfer

Question 30

Define amplitude

Answer 30

The maximum extent of a vibration of a wave

Question 31

Define interference

Answer 31

Two waves superpose to form a resultant waves of greater less or equal amplitude

Question 32

Define phase difference

Answer 32

The position in a wave

Question 33

Define a real image

Answer 33

Where two waves meet from a lens. Can be projected on a screen

Question 34

Define a virtual image

Answer 34

Image formed from apparent divergence of waves

Question 35

Define plane polarisation

Answer 35

Restricting the vibrations of EM radiation to one direction

Question 36

Define diffraction

Answer 36

Bending of light around an object

Question 37

Define the pulse echo technique

Answer 37

Non destructive testing using ultrasound waves to detect defects in materials

Question 38

List diffraction experiments

Answer 38

Using a laser through tiny slits onto a wall and measuring the distance in between the dots produced

Question 39

What is intensity of radiation?

Answer 39

How much energy reaches an area per second

Question 40

Define path difference

Answer 40

The difference between two waves

Question 41

How do noise cancelling headphones work?

Answer 41

They produce a wave that is 180 degrees out of phase to the surrounding waves of sound so that they superpose destructively (destructive interference) to cause an overall output of 0

Question 42

What is a node?

Answer 42

A point along the wave where it has a minimum amplitude

Question 43

What is an antinode?

Answer 43

A position of maximum amplitude on a wave