Light & Waves

Question 1

Wave

Answer 1

Transfer of energy but not matter

Question 2

Transverse Wave

Answer 2

Oscillations are perpendicular to the transfer of energy
- S waves
- light

Question 3

Longitudinal Wave

Answer 3

Oscillations are parallel to the direction of energy transfer
- P waves
- sound

Question 4

Wavelength λ

Answer 4

The shortest distance between two points on a wave that are in phase

Question 5

Frequency

Answer 5

The number of oscillations per second (Hz)

Question 6

Time Period

Answer 6

The time taken for one oscillation (s)

Question 7

Peak

Answer 7

The maximum positive displacement of a wave

Question 8

Trough

Answer 8

The maximum negative displacement of a wave

Question 9

Equilibrium Position

Answer 9

The rest position of the medium if there wasn’t a wave moving through it

Question 10

Amplitude

Answer 10

The maximum displacement of a wave

Question 11

Displacement

Answer 11

The distance a point is from the equilibrium

Question 12

Wavefront

Answer 12

A line representing the points on a wave that are all in phase and the same distance from the source of the wave

Question 13

In Phase

Answer 13

Waves that have identical physical properties
- speed
- velocity
- displacement
- acceleration

Question 14

Anti-phase

Answer 14

When points on a wave has opposite physical properties

Question 15

Transmission

Answer 15

When a wave passes through a material

Question 16

Absorption

Answer 16

When a wave’s energy is transferred to the material it passes through

Question 17

Reflection

Answer 17

When a wave bounces off an interface between two different media, back to its original medium

Question 18

Specular Reflection

Answer 18

Waves reflecting parallel to each other off a smooth surface

Question 19

Diffuse Reflection

Answer 19

Waves reflecting off an irregular surface in random directions

Question 19

Diffuse Reflection

Answer 19

Waves reflecting off an irregular surface in random directions

Question 20

Primary Colours

Answer 20

Red
Blue
Green

Question 21

Secondary Colours

Answer 21

Magenta
Cyan
Yellow

Question 22

White Light

Answer 22

Contains all colours on the spectrum
Mixing all three primary colours produces white light

Question 23

Filter

Answer 23

Absorbs some colours and allows other colours to transfer through the filter

magenta object + red filter = blue object

red object + red filter = black object

Question 24

Speed of Light

Answer 24

3 x10⁸ m/s

Question 25

Refraction

Answer 25

When light enters a medium of different density and changes speed. The change in speed causes the ray to bend. The wavelength changes but frequency always stays the same

Question 26

Incident Ray

Answer 26

The ray of light entering the new medium

Question 27

Refracted Ray

Answer 27

The ray of light that gets bent in the second medium

Question 28

Emergent Ray

Answer 28

The ray of light that leaves the second medium and returns to it's original velocity

Question 29

Angle of Incidence

Answer 29

The angle from the normal to the ray of incidence

Question 30

Angle of Refraction

Answer 30

The angle from the normal to the refracted ray

Question 31

Critical Angle

Answer 31

The angle from the normal to the incident ray when the refracted ray is parallel to the surface of the medium

Question 32

Total Internal Reflection

Answer 32

When the angle of incidence is greater than the critical angle, all of the light is reflected back

Question 33

Fibre Optic Cables

Answer 33

Thin glass cables that transmit binary values in pulses of light using total internal reflection

Question 34

Convex Lens

Answer 34

(Converging lens) Outwards bend Parallel rays of light that are parallel to the principal axis will refract inwards and converge at the focal point

Question 35

Concave Lens

Answer 35

(Diverging lens) Inward bend Parallel rays of light will refract away from each other. Adding virtual rays to the diagram show the rays crossing at the nearside focal point

Question 36

Virtual Images

Answer 36

When real rays do not meet. Virtual rays can be drawn to form a virtual image. They cannot be projected onto a screen. Mirrors

Question 37

Real Images

Answer 37

When real rays meet to form a real image. They can be projected onto a screen

Question 38

Power of a Lens

Answer 38

P = 1/focal length measured in dioptres

Question 39

Focal Length

Answer 39

The distance between the (optical) centre of the lens to the focal point

Question 40

Magnified

Answer 40

When the image is bigger than the object

Question 41

Diminished

Answer 41

When the image is smaller than the object

Question 42

Magnification

Answer 42

image height / object height

Question 43

S Waves

Answer 43

- Transverse - Only travel through solids → shadow zone - Slower but more destructive (oscillate perpendicularly to energy transfer)

Question 44

P Waves

Answer 44

- Longitudinal - Travel through solids + liquids - Faster but less destructive