SNC1D: PHYSICS UNITS Electricity Exam Review

Static Electricity an imbalance of electric charge on the surface of an object (“static” means unmoving)

Current Electricity the controlled flow of electric charge

Conductor a material that allows charge to flow freely through it (example: copper wire)

Insulator a material that does not allow charge to flow freely through it (example: plastics) (Insulators are better at holding static charge because the charges can’t flow.)

Law of Static Charge Unlike charges attract. Like charges repel. Charged attract neutral objects.

Law of Static Charge If two charged ebonite rods (rubbed with fur) are brought close together they will repel each other because they will have the same charge.

Charge Transfer

Grounding If an object with a positive charge is grounded, electrons will flow up from the ground to neutralize it. If an object with a negative charge is grounded, electrons will flow down to the ground to neutralize it.

Current the rate of flow of electric charge ( I, measured in Amperes or A)

Resistance opposition to the flow of charges ( R, measured in Ohms or  )

Potential Difference the energy carried by the electrical charges ( V, measured in Volts or V)

Power the rate at which energy is produced or consumed ( P, measured in Watts or W)

Ohm’s Law

If a light bulb filament with a resistance of 85 Ω, is connected to a 110 V circuit, how much current is travelling through the bulb?

Schematic Diagram a 3 cell battery, a switch, two lamps in series, with a voltmeter recording the potential difference across the first lamp

Series Circuit a circuit in which there is only one path for current

Parallel Circuit a circuit in which there is more than one path for current

Circuit Diagram A 3-cell battery, a switch, two light bulbs in series, an ammeter measuring the current in the circuit, and a voltmeter recording the potential difference across one of the bulbs.

GUSS: Power If the heating element of a toaster uses 110 V and draws 12 A of electricity, what is the power consumed by the heating element?

Efficiency the ratio of the useful energy output to the energy input

Energy Cost

Batteries A battery produces direct current.

Generators Generators produce alternating current. Something turns a turbine attached to a giant magnet. The changing magnetic field induces a current flow in a coil of wire.

Energy Sources Renewable: Non-renewable: coal, oil, uranium, etc.

Fuse A parallel circuit is more likely to require a fuse because the lower equivalent resistance will draw a higher current.

Circuit Analysis