Unit 3
Unit 3-1 Concept 1 explaining the source of magnetic characteristics of matter in terms of magnetic domains
Magnets are made up of tiny regions called domains which act like tiny bar magnets. When These domains are in the same direction the material is a magnet, when they are random, the object is a ferromagnetic material. The reason a magnet is attracted to ferromagnetic material is because the external field of the magnet aligns the domains of the ferromagnetic material making it a temporary magnet. Materials which do not have domains therefore do not stick to magnets.
Unit 3-1 Concept 2 comparing the magnetic properties of Earth with those of artificial magnets
Unit 3-1 Concept 3 explaining magnetic interactions in terms of vector fields
Like all fields, Magnetic fields add as vectors. i.e. A magnetic field of 2.0 T east and a 3.0 T field west interact to create a 1.0 T field west.
Unit 3-1 Concept 4 comparing
gravitational, electric and magnetic fields in terms of their sources and directions.
No explanation necessary
Unit 3-2 Concept 1 demonstrating how the discoveries of Oersted and Faraday form the
foundation of the theory relating electricity to magnetism
Oersted showed that a moving charge produced a magnetic field and Faraday showed that a moving magnetic field (change in flux) would produce a voltage and therefore an electrical current.
Unit 3-2 Concept 2 describing
a moving charge as the source of a magnetic field; and predicting the orientation
of the magnetic field from the direction of motion
A moving charge will produce a magnetic field that encircles the charge perpendicular to the charge's motion.
Unit 3-2 Concept 3 predicting,
quantitatively, how a uniform electric and/or magnetic field affects a moving electric
charge, using the relationships among charge, motion and field direction
F=BIL
F=Bqv
To find the direction on a charge use your left hand place your
thumb in the direction of negative charge motion (for positive charges use right
hand). Point your index finger in the direction of the magnetic field and your palm
or middle finger will point in the direction of the force on the charge.
Unit 3-2 Concept 4 relating and explaining, qualitatively, the interaction between
a magnetic field and a moving charge as to how a magnetic field affects a current-carrying
conductor
This is nearly the same as the previous topic except the charges are now confined to a conductor. The force on the charge is now the force on the wire.To find the direction of force on current carrying wire use your left hand and place your thumb in the direction of electron flow (for conventional current use right hand). Point your index finger in the direction of the magnetic field and your palm or middle finger will point in the direction of the force on the wire.
Unit 3-2 Concept 5 predicting, quantitatively,
the effect of an external magnetic field on a current-carrying conductor
Force on a wire can be determined using
Unit 3-2 Concept 6 describing the effects of moving a conductor in an external magnetic field, using the analogy of a moving charge in a magnetic field
or 
Moving a wire in a magnetic field is similar to moving a charge in a magnetic field because of the free electrons in the wire. The force produced on the free electrons in the wire results in a voltage potential. The direction of the charge is the direction the wire is moving and the resulting force on the free electrons in the wire is the direction of the induced electron flow.
Unit 3-2 Concept 7 predicting, quantitatively, the effects of a magnetic field on a moving conductor
A moving wire in a magnetic field will produce an induced voltage
Unit 3-2 Concept 6 predicting, quantitatively, and verifying, the effects of changing one, or a combination, of the variables in the relationship
In a transformer the power in and out of the transformer is the same but the voltage and amperage can be varied depending on the number of wraps of wire placed on the primary and secondary sides of the transformer.
Unit 3-2 Concept 8 explaining the relationship between, and calculating, the effective and maximum values of, voltage and current in AC devices, given appropriate information
In the production of an electric current which switches from a maximum positive voltage to a maximum negative voltage. The effective voltage is the sin wave averages on the positive or negative not the overall average. The induced voltage produces the induced current and according to ohms law they vary proportionally to each other. The reason Power maximum is twice the effective is because power is product of the voltage and amperage and if you multiply the voltage effective and amperage effective it equals half. (0.707 x 0.707 = 0.5)
Unit 3-2 Concept 9 discussing, qualitatively,
Lenzs law in terms of conservation of energy; describing, giving examples, situations
where Lenzs law applies.
Lenz law states: an induced current produces a magnetic field which opposes the magnetic field which produced it.
If this was not the case and the induced current would produce a magnetic field which would attract the magnet which produced the current adding energy to the system without energy being added breaking the law of conservation of energy.
Unit 3-3 Concept 1 stating
that electromagnetic radiation is the result of accelerating electric charges, and
demonstrates wavelike behavior
Self Explanatory
Unit 3-3 Concept 2 comparing
and contrasting the constituents of the
electromagnetic spectrum on the basis of frequency, wavelength and energy
Compare the entire EM spectrum from Radio waves Low frequency, short wavelength, low energy electromagnetic waves through microwaves, infrared, visible light, ultraviolet, x-rays to short wavelength high frequency high energy gamma ray photons.
Unit 3-3 Concept 3 solving
problems algebraically, using the relationships among speed, wavelength, frequency,
period and/or distance, of electromagnetic waves
All electromagnetic waves travel at the speed of light
and obey the formula
c = fl
c = speed of light 3.0 x 108 m/s
f = frequency of light in hertz Hz or waves / s
l = wavelength of light in metres
m
Since EM waves travel at the a constant speed calculation of distance and time can be found from
v = d / t
v = velocity in m/s
d = change in displacement
t = change in time
Unit 3-3 Concept 4 comparing and
contrasting natural and technological processes by which the major constituents of
the electromagnetic spectrum are produced
Electromagnetic waves are produced by accelerating charges. The greater the acceleration the higher frequency of electromagnetic radiation produced.
Unit 3-3 Concept 5 explaining, qualitatively, Maxwells theory of electromagnetism
Maxwell predicted the speed of a wave of ocilating electric and magnetic fields which could travel in a vacuum. Since his theoretical value of c matches the measured value we can infer light is an electromagnetic wave.
Unit 3-3 Concept 6 explaining the propagation of electromagnetic radiation in terms of perpendicular electric and magnetic fields, varying with time, travelling away from their source at the speed of light
Self Explanatory
Unit 3-3 Concept 6 explaining, qualitatively, how different types of electromagnetic radiation interact with matter, including biological effects; e.g., microwaves, ultraviolet radiation, X-rays.
One main concern is microwaves which can heat water and damage living tissue which is made up largely of water. This heating is not do to their energy of singular photons, rather it is caused by a series of photons that are resonate with water each adding energy in phase. The other concern is about ionizing radiation. (UV to gamma) Ionizing radiation has enough energy to know an electron out of an atom forming an ion. This ion can be a source of cancer.