Week 3- Electromagnetic And Optical Radiation

Question 1

Define radiation

Answer 1

radiation is the emission or transmission of energy in the form of waves or particlesthrough space (a vacuum) or through a material medium (e.g. air

Question 2

Define electromagnetic radiation

Answer 2

air)§ electromagnetic radiation: such as radio waves, microwaves, infrared, visible light,ultraviolet, x-rays, and gamma radiation (γ)§

Question 3

Define particle radiation

Answer 3

(γ)§ particle radiation: such as alpha radiation (α), beta radiation (β), and neutron radiation§

Question 4

Examples of acoustic radiation

Answer 4

§ acoustic radiation: such as ultrasound, sound, and seismic waves (dependent on aphysical transmission medium)§

Question 5

Examples of gravitational radiation

Answer 5

gravitational radiation: radiation that takes the form of gravitational waves, or ripples in thecurvature of spacetime

Question 6

What are all waves carried by

Answer 6

some form of oscillation, e.g. sound waves arecarried by oscillating gas molecules, and electromagnetic waves are carriedby oscillating electric and magnetic fields

Question 7

Name forms in which waves appear

Answer 7

Sound, heat,light, x-rays

Question 8

What is oscillation

Answer 8

Oscillation is the repetitive variation (typically in time) of some measureabout a central value (often a point of equilibrium

Question 9

What is vibration

Answer 9

)§ Vibration is the term that is precisely used to describe mechanical oscillation

Question 10

Name the 2 types of waves

Answer 10

Longitudinal
Transverse

Question 11

What do longitudinal waves require

Answer 11

A medium through which to travel

Question 12

What can’t longitudinal waves travel through

Answer 12

A vacuum

Question 13

Describe longitudinal waves

Answer 13

Longitudinal waves require a medium through whichto travel (i.e. cannot travel through a vacuum).

The particles of the transmitting medium are displaced along the direction of propagation

Question 14

Describe transverse waves

Answer 14

Transverse waves do not always require a medium through which to travel.

The displacement of any transmitting medium is perpendicular to thedirection of propagation

Question 15

What is the amplitude

Answer 15

Largest displacement encountered during oscillation

Question 16

What is the wavelength

Answer 16

Distance between two consecutive point (two peaks, two troughs)

Question 17

What is the period

Answer 17

Period of an oscillation is the time taken to complete one cycle

Question 18

What is the frequency of any oscilation

Answer 18

Number of cycles completed every second

Question 19

What is frequency measured in

Answer 19

Herts
HZ
S-1

T= s

Question 20

Give the equation to work out frequency

Answer 20

F= 1/t

T= 1/F

Question 21

What is the speed

Answer 21

Unitdistance traveled by a cycle per unit of time

Question 22

Give equations for speed

Answer 22

C=. Distance/ time

Wavelength/ time = speed

Wavelength x frequency

Question 23

When can velocity change

Answer 23

When traveling from one medium to another

Question 24

What has an inverse relationship with frequency

Answer 24

Wave length to allow speed to remain constant

Question 25

How do electromagnetic waves travel

What do they exhibit

Answer 25

In a straight line

Rectilinear propagation

Question 26

Define radiation intensity

Answer 26

§ The energy carried by a wave can be described by the concept of intensity (

I)§ Radiation intensity (I) is defined as the quantity of radiation energy passing though a unit-area per unit of tim

Question 27

Give an equation to work out intensity

Answer 27

Energy per second/ area

Question 28

Explain inverse square law

Answer 28

Total amount of radiation in beam doesn’t change

Conc (intensity) descreases with increasing distance from the source

Question 29

What is thr EM spectrum

Answer 29

Electromagnetic radiation organised by frequency and wavelength in a sequential order

Grouped in many sub ranges (visible light, ultraviolet radiation)

Divisions identified by differences in behaviour, emission, transmission, absorption of corresponding waves

Question 30

What is the energy of a photon proportional to

Answer 30

Wave frequency

Question 31

what is an electronvolt

Answer 31

electron after it has been accelerated from rest through a potential difference of one volt

Question 32

what is an electric current through an area defined as

Answer 32

the net charge flowing through any point of wire per unit time

Question 33

give the equation to work out electric current

Answer 33

Q= I T
q= electric charge
i= electric current
t= time

Question 34

when can an electrical current flow

Answer 34

when something pushes it

Question 35

what is electrical voltage

Answer 35

the pressure that pushes the electrons within an electrical wire, allowing them to flow through the wire

Question 36

where does the push for electron voltage come from

Answer 36

the difference in potential energy at the start and the end of an electrical circuit