Right Hand Rules #1 & #2

OERSTED'S PRINCIPLE: Charge moving through a conductor produces a circular magnetic field around the conductor

RHR#1



RIGHT-HAND RULE #1 (RHR#1) for conventional current flow: Grasp the conductor with the humb of the right hand pointing in the direction of conventional, or positive (+), current flow. The curved fingers point in the direction of the magnetic field around the conductor.



RHR#2



RIGHT-HAND RULE #2 (RHR#2) for conventional current flow: Grasp the coiled conductor with the right hand so that the curved fingers point in the direction of conventional, or positive (+), current flow. The thumb points in the direction of the magnetic field within the coil. Outside the coil, the thumb represents the north (N) end of the electromagnet produced by the coil.

Check out this awesome video:

Magnetic Force /Electromagnets

MAGNETIC FIELD: distribution of a magnetic force in the region of a magnet.
- Two different magnetic characteristics labelled North and South

- Similar magnetic poles, north and north or south and south REPEL one another with force
- Dissimilar poles, north and south, ATTRACT one another with a force

The law of magnetic forces

TEST COMPASS: a compass used to check for the presence of a magnetic field

FERROMAGNETIC METALS: metals such as iron, nickel, cobalt or mixtures of these three that attract magnets

DOMAIN THEORY: All large magnets are made up of many smaller and rotatable magnets, called dipoles, which can interact with other dipoles close by. If dipoles line up, then a small magnetic domain is produced.

Dipoles: the small and flexable magnets that make up a large magnet

Magnetic domain: the effect produced when dipoles of a magnet line up

Resistance/Ohm's Law/Kirchhoff's Law

RESISTANCE:  a measure of the opposition to current flow  

•  the amount of current flow in a circuit depends on two things: 

1)  the potential difference of the power supply
2) the nature of the pathway through the loads 

OHM'S LAW:

• Graphing the Linear Equation for Ohm's Law from Data:

• Factors that Affect Resistance:

- Length: longer the conductor, the greater the resistance
- Cross-sectional area: the larger/thicker conductor, less resistant it has to charge flow
- Type of material: resistivity is measure of resistance of a substance
- Temperature: greater molecular motion at higher temperature increases the resistance

• SUPERCONDUCTIVITY: ability of a material to conduct electricity without heat loss due to electrical resistance.

KIRCHHOFF'S CURRENT LAW:
The total amount of current into a junction point of a circuit equals the total current that flows out of that same junction.

KIRCHHOFF'S VOLTAGE LAW:
The total of all electrical potential decreases in any complete circuit loop is equal to any potential increases in that circuit loop.

• In other words, there is no net gain or loss of elecric charge or energy

Kirchhoff's laws in a SERIES circuit:
VOLTAGE: Voltage must be distributed so that the sum of all voltage drops must equal this value.

VT= V1 + V2 + V3

CURRENT: The circuit only has one path to flow.

IT= I1 = I2 = I3

Kirchhoff's laws in a PARALLEL circuit:
VOLTAGE: Voltage drops have to remain the same no matter what.

VT= V1 + V2 + V3

CURRENT: the sum of the current entering junctions must equal the sum of the current exiting them.

IT= I1 + I2 + I3

RESISTANCE IN SERIES:

RT = R1 + R2 + R3 .... + RN

(N is the total number of series resistors in the circuit)

RESISTANCE IN PARALLEL:

1/RT = 1/R1 + 1/R2 + 1/R3 .... + 1/RN

You can rewatch the video on RESISTANCE :)

Prelab Table

Completing the Circuit

What is the difference between a series and parallel circuit?

( A circuit is the path that electricity follows. )

All of the electricity
follows path #1

SERIES CIRCUIT: In a series circuit, the parts of the circuit (such as the battery, a switch, and the electric device) are connected one after another (in series) in a single closed loop. A series circuit allows electrons to follow only one path. The loads in a series circuit must share the available voltage. In other words, each load in a series circuit will use up some portion of the voltage, leaving less for the next load in the circuit. This means that the light, heat, or sound given off by the device will be reduced. If one device (e.g. bulb) in series burns out, the circuit is broken and there is no other path for the flow of charges therefore the other devices no longer work.

Some current follows path #1,
while the remainder splits
off from #1 and follows path #2

PARALLEL CIRCUIT: In parallel circuits, all the devices share a common connection to the voltage source. Different devices are on separate "parallel" branches. In parallel circuits, the electric current can follow more than one path to return to the source, so it splits up among all the available paths. Across all the paths in a parallel circuit the voltage is the same, so each device will produce its full output. There are different paths for currents such that a break in the flow of charges in one path does not interrupt the flow along other paths.

 

“To give an analogy of each circuit, in a series circuit, a postman has something to deliver to only one house; and in a parallel circuit, the postman has things to deliver to two houses. In a series circuit, if a part of the route gets destroyed, the postman cannot deliver whatever has to be delivered; in a parallel circuit, if one route becomes impassable for whatever reason, the postman can still reach one house.” - EC

Check out this awesome video on this topic.