Unit 1 Terminology PW1

Question 1

Electromagnetic Spectrum

Answer 1

the range of wavelengths that light can exist in

Question 2

Luminous body

Answer 2

an object that emits light ex. sun

Question 3

Non-luminous body

Answer 3

does not emit light, but reflects and absorbs it, sometimes called illuminated ex. book/desk

Question 4

Incandescent

Answer 4

emits light when heated, the type/colour depends on temp ex. fire poker

Question 5

Rectilinear propagation

Answer 5

light travels naturally in a straight line, unless acted upon by gravity

Question 6

Transparent

Answer 6

objects transmit light while absorbing/reflecting ex. glass/window

Question 7

Translucent

Answer 7

allows light to pass through, scatters and transmit light ex. frosted window

Question 8

Opaque

Answer 8

an object either absorbs or reflects specific wavelengths ex, desk/book

Question 9

Rays

Answer 9

A way to represent light on paper, doesn’t actually exist in nature

Question 10

Beam

Answer 10

a collection or rays

Question 11

Shadows

Answer 11

when an opaque object blocks the light

Question 12

Umbra

Answer 12

A total shadow, crisp outlines

Question 13

Penumbra

Answer 13

A partial shadow, fuzzy outlines

Question 14

Wave

Answer 14

the transfer of energy in the form of a disturbance propagating through a medium

Question 15

Transverse Waves

Answer 15

occur when the vibration of the medium if perpendicular to the direction of the energy transfer

Question 16

Crest

Answer 16

the maximum position of a transverse wave

Question 17

Trough

Answer 17

the minimum position of a transverse wave

Question 18

Amplitude

Answer 18

the maximum displacement from the equilibrium

Question 19

Equilibrium

Answer 19

the point of balance, rest position

Question 20

Wavelength

Answer 20

the distance between successive crests or troughs, represented by lambda

Question 21

Longitudinal Waves

Answer 21

occur when the medium vibrates parallel to the direction of energy transfer, caused by the compressing and recoiling of the particles

Question 22

Compressions

Answer 22

regions with little space between particles

Question 23

Rarefactions

Answer 23

areas where particles are more spaced out

Question 24

Pulse

Answer 24

a wave with a short duration

Question 25

Cycle

Answer 25

one complete passing of a wave

Question 26

Periodic Motion

Answer 26

waves that vibrate in repeating cycles, also called harmonic motion

Question 27

Frequency (f)

Answer 27

the number of cycles passing by a certain point in a certain time, represented by Hz

Question 28

Period (T)

Answer 28

the time required for a full wave to pass by a certain point

Question 29

Intensity

Answer 29

related to wavelength and frequency, the longer the wavelength and smaller the frequency the less the intensity

Question 30

Universal Wave Equation

Answer 30

the relationship between speed, frequency, and wavelength. Applies to all waves, even those that aren't electromagnetic. V=flambda

Question 31

Transmission

Answer 31

the process of a wave transferring it's energy from one medium to another. The frequency remains the same.

Question 32

Reflection

Answer 32

A wave is reflected back in it's original direction

Question 33

Fixed-end reflection

Answer 33

The wave will bounce back in the original direction but inverted.

Question 34

Damping

Answer 34

When the amplitude of the returning wave is smaller than that of the original. Some energy is lost to the barrier.

Question 35

Free-end Reflection

Answer 35

The wave returns in it's original direction not inverted.

Question 36

Partial Reflection

Answer 36

Occurs at the boundary, some of the energy in transmitted.

Question 37

Interference

Answer 37

When two or more waves act simultaneously on a medium.

Question 38

Principle of Superposition

Answer 38

When two or more waves pass through each other the displacement can be found by adding those of each wave.

Question 39

Constructive Interference

Answer 39

Occurs when the resulting disturbance is greater than the individual disturbance.

Question 40

Destructive Interference

Answer 40

Occurs when the resulting disturbance is smaller than the individual disturbances.

Question 41

Standing Wave

Answer 41

A interference pattern with both maximum constructive and destructive interferences. Appears in such a way that looks as though the wave doesn't move along the string.

Question 42

Nodes

Answer 42

The points where the medium meets the equilibrium

Question 43

Antinodes

Answer 43

The top/bottom point of crests or troughs.

Question 44

Rules of Standing Waves

Answer 44

1. There must be two or more waves of the same frequency. One or both must be a reflected wave. 2. There must either be a whole or half number of wavelengths.