Week 3- Electromagnetic And Optical Radiation Flashcards

1
Q

Define radiation

A

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

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2
Q

Define electromagnetic radiation

A

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

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3
Q

Define particle radiation

A

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

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4
Q

Examples of acoustic radiation

A

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

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5
Q

Examples of gravitational radiation

A

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

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6
Q

What are all waves carried by

A

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

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7
Q

Name forms in which waves appear

A

Sound, heat,light, x-rays

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8
Q

What is oscillation

A

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

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9
Q

What is vibration

A

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

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10
Q

Name the 2 types of waves

A

Longitudinal
Transverse

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11
Q

What do longitudinal waves require

A

A medium through which to travel

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12
Q

What can’t longitudinal waves travel through

A

A vacuum

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13
Q

Describe longitudinal waves

A

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

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14
Q

Describe transverse waves

A

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

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

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15
Q

What is the amplitude

A

Largest displacement encountered during oscillation

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16
Q

What is the wavelength

A

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

17
Q

What is the period

A

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

18
Q

What is the frequency of any oscilation

A

Number of cycles completed every second

19
Q

What is frequency measured in

A

Herts
HZ
S-1

T= s

20
Q

Give the equation to work out frequency

A

F= 1/t

T= 1/F

21
Q

What is the speed

A

Unitdistance traveled by a cycle per unit of time

22
Q

Give equations for speed

A

C=. Distance/ time

Wavelength/ time = speed

Wavelength x frequency

23
Q

When can velocity change

A

When traveling from one medium to another

24
Q

What has an inverse relationship with frequency

A

Wave length to allow speed to remain constant

25
How do electromagnetic waves travel What do they exhibit
In a straight line Rectilinear propagation
26
Define radiation intensity
§ 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
27
Give an equation to work out intensity
Energy per second/ area
28
Explain inverse square law
Total amount of radiation in beam doesn’t change Conc (intensity) descreases with increasing distance from the source
29
What is thr EM spectrum
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
30
What is the energy of a photon proportional to
Wave frequency
31
what is an electronvolt
electron after it has been accelerated from rest through a potential difference of one volt
32
what is an electric current through an area defined as
the net charge flowing through any point of wire per unit time
33
give the equation to work out electric current
Q= I T q= electric charge i= electric current t= time
34
when can an electrical current flow
when something pushes it
35
what is electrical voltage
the pressure that pushes the electrons within an electrical wire, allowing them to flow through the wire
36
where does the push for electron voltage come from
the difference in potential energy at the start and the end of an electrical circuit
37