WK4- Electromagnetic Energy

what is Electromagnetic Energy Spectrum?

continuous range of energy

+spectrum indicates that the distribution of energies exist in an uninterrupted band

what is Electromagnetic Energy?

energy that moves through space or matter as oscillating(up&down/back&forth) magnetic & electric fields

what are the general characteristics of electromagnetic energy spectrum?

-no mass or physical form

-travel at speed of light in a vacuum(or air)

-travel in a linear path

-dual nature: act both as wave or particle

-unaffected by electric or magnetic fields and gravity

what is the formula for speed of light

represented by "c"

c = 3 x 10^8 m/s

what is a wavelength?

distance traveled by wave in a single cycle

what is the unit of a wavelength?

meter

(could be mm/cm/m)

what is a cycle?

one complete wave form or repetition. (1cycle=1 neg+1pos)

what is the positive and negative alternations of a wave called?

crest-positive alternation

trough-negative alternation

what is amplitude?

the max displacement from equilibrium(zero)

what is frequency?

the number of cycles per unit time (s).

(represented as f or v)

what is the unit for frequency?

hertz (Hz)

what is velocity and its unit?

velocity is the speed each cycle travels.

its unit is m/s

v of Em radiation always equals what?

velocity of electromagnetic radiation always equals c

v of EM radiation always = c

(c is for constant aka speed of light )

what is the formula for finding wavelength's frequency?

WL = C / F

what is the formula for constant?

c=3x10^8m/s

c - (speed of light)

C = F x WL

what is the formula for finding frequency's wavelength?

F = C / WL

what is the formula for Energy?

E (ev) = h (f)

what is the usual energy unit for Energy?

J

1 J = 6.24 x 10^18 eV

what is the Planck's constant formula & what is it represented as?

represented as h

h = 4.15 x 10^-15 eVs

xrays and gamma rays are usually measure in ?

keV

as energy decreases, frequency _____________

as energy decreases, frequency decreases

what is the formula for frequency and energy?

F = ev /h

what is the formula for wavelength and energy? and its unit?

wl= 12.4 / kev ---unit:A

what is attenuation?

reduction in the number of xray photons

what is refraction?

-deviation in the line of travel of a light photon

-xrays cannot be refracted but scattered

what is radiolucent?

xrays easily penetrate(easily penetrable)

ex-air-goes right through it

what is radioopaque?

xrays are absorbed

ex-bone, metal

what are beta particles?

like electrons except originate in nucleus of radioactive isotopes

what are gamma rays?

like xrays except originate in nucleus of radioactive isotopes

what are xrays in air?

xrays in air are roentgen using units or R or mR

what is the inverse square law and its formula?

radiation intensity is inversely proportional to the square of the distance

I d^2

___ = _____

i D^2