Lecture 1

Question 1

Lorentz force equation

Answer 1

F = qE +qb*B

Question 2

Gauss’s law

Answer 2

electric fields are generated by single charges and diverge

Question 3

Gauss’s law (magnetism)

Answer 3

No magnetic charge magnetic fields are generated by dipoles and not originate in a single point

Question 4

Faraday’s law of induction

Answer 4

a spatially varying electric field is accompanied by a temporary varrying magnetic field

Question 5

Ampere’s law

Answer 5

magnetic fields can be generated in two ways: by electric currents and changing electric fields

Question 6

permeability

Answer 6

the ability of a medium to support magnetic fields

Question 7

permittivity

Answer 7

the capactance encountered when forming an electric field in a medium. In other words, the energy-storage capacity of the field in the medium

Question 8

descibe the properties of light

Answer 8

light is an electromagnetic wave, carries electric and magnetic fields, allowing it to interact with electric charges

Question 9

describ light waves

Answer 9

light waves have a frequency, a wavelength, a certain energy, as well as given momentum.

Question 10

Light equations

Answer 10

c=入V
E=hv=hc/入
p=E/c

Question 11

light properties

Answer 11

Light can also have a polarization, that is, the wave might oscillate in a specific plane of
the electric field. If you have polarized sunglasses, you can try holding them up to your
computer screen and then rotating them 90 degrees while keeping your head upright!

Question 12

light properties

Answer 12

As light is a wave, sets of these waves can be in or out of phase with each other. The
relationship between these phases is called coherence.

Question 13

Light is also a particle

Answer 13

Light is also a particle! Photons have mass, and, as such, light will interact with gravity.
Photons can also interact with each other.

Question 14

Photons are categorized as

Answer 14

Photons are categorized as “bosons”: more than one photon can occupy a given state.
This means light obeys Bose-Einstein statistics.

Question 15

All objects emit radiation(light)

Answer 15

All objects emit radiation (light) due to accelerated charges at T>0K; thermal radiation (black body radiation)

Question 16

Stephan-Boltzman law

Answer 16

P = SigmaAT^4
sigma = (2pi^5k^4)/(15c^2h^3) = 5.670373*10^-8 WM^-2K^-4

Question 17

heat transfer can be calculated

Answer 17

Pnet = Pemit - Pabsorb
Pnet = AsigmaE(T^4-T0^4)

Question 18

light emiited from higher energy level to lower energy level

Answer 18

E2-E1 = delta E = hv

Question 19

Lasers differ from other light sources for a few reasons

Answer 19

They operate using a single wavelength, and, as such, are monochromatic.
* They are coherent.
* They are directional. This means the light is spatially targeted, the light barely
diverges. This contrasts with flashlights, for example.
* They are polarized.

Question 20

Lasers come in two varieties, continuum wave (CW) and pulsed

Answer 20

Continuum wave lasers operate at a constant output power with no
interruptions in the beam of light.
* Pulsed lasers operate at similar average power outputs to the CW laser, but only
emit light intermittently and for very short periods of time. As such, the power
output per burst is much greater than that of CW lasers.

Question 21

Lasers have many practical applications

Answer 21

Optical tweezers
* Medical purposes (eg.: LASIK)
* Motion detection
* Mass spectroscopy
* Scanning
* DNA sequencing