Electricity

Question 1

What is the charge of a Neutral Object?

Answer 1

Does not have any charge, (protons = electrons)

Question 2

What makes Charged objects charged objects?

Answer 2

They have either lost or gained charge, Positive lost, (+) and negative gains, (-)

Question 3

What is the Law of electric charges?

Answer 3

Opposites attract, and like charges repel.

Question 4

What are the Three Methods that can be used as a charge?

Answer 4

Created by friction, contact and induction.

Question 5

What is charging by Friction?

Answer 5

By rubbing two different substances together, the substances can be given an electric charge. Electrons move from one object to the other (one substance loses electrons and the other gains electrons). The object that loses electrons becomes positive (these objects have a weak hold on electrons). The object that gains electrons becomes negative (these objects have a strong hold on electrons).

Question 6

What is charging by friction cont.?

Answer 6

Between the two substances, the higher one loses electrons (becomes positive) and the lower one gains electrons (becomes negative).

Ex: Glass is above Sulfur, so the Glass becomes positively charged and the Sulfur becomes negatively charged.

Question 7

What is the Electrostatic Series?

Answer 7

The Electrostatic Series determines the kind of charge produced on each substance when any two substances are rubbed together.

Question 8

What is charging by contact (conduction)?

Answer 8

If an already existing charged object contacts a neutral object, the second object will become charged by gaining or losing electrons. The type of charge will be the same as that of the first object, meaning the two objects will now repel each other (like charges repel).

Question 9

What happens when a negatively charged rod contacts a neutral sphere?

Answer 9

After contact, the electrons transfer to the neutral sphere making it the same charge (negative) as the negative rod.

Question 10

What is Charging by Induction?

Answer 10

If a charged object is brought close to (but not in contact with) a neutral object, the electrons will be attracted or repelled depending on the charge of the object.

Question 11

What is Grounding?

Answer 11

A grounding wire may be added. A ground connects to the Earth (can gain or lose many electrons and remain neutral). When an object is grounded, it becomes neutral.

Question 12

What is Electric Discharge?

Answer 12

Caused when two objects with a charge imbalance are brought close together and a rapid electron transfer occurs → creates a spark. Electrons move from the more negative object to the less negative one. The greater the charge difference, the larger the shock/discharge.

Question 13

What is the difference between a conductor and an insulator?

Answer 13

Conductor: A material that allows heat and electricity to flow through it.

Insulator: A material that does not allow heat and electricity to flow through it.

Question 14

What is Current Electricity?

Answer 14

In Current Electricity, the electrons constantly flow along a conductor.

Question 15

What is Current?

Answer 15

The movement of electron flow, measured in Amperes (A). Current is a measure of how many electrons pass a point each second (not the speed of electrons). More electrons = More Current.

Formula: I = Q/t

Question 16

What is Potential difference?

Answer 16

Otherwise known as voltage. It is the loss in energy.

Formula: V = E/Q

Question 17

What does an Ammeter measure?

Answer 17

Current.

Question 18

What does a Voltmeter measure?

Answer 18

Voltage.

Question 19

What does a multimeter measure?

Answer 19

Current, voltage and other variables.

Question 20

What does a circuit require?

Answer 20

Source (battery), Load (lightbulb), Conductor (wires).

Question 21

What is the role of the Source in a circuit?

Answer 21

Provides the charges in the circuit with energy. (ex: Battery)

Question 22

What is the role of the Load in a circuit?

Answer 22

Uses the energy carried through the circuit by the charges. (ex: lightbulb)

Question 23

What is the role of the Conductor in a circuit?

Answer 23

Allows the charges to flow from one component to another. (ex: wires)

Question 24

What is the role of Control in a circuit?

Answer 24

Allows the flow of charge to be stopped/started (ex: switch).

Question 25

What are the Electrical Circuit Rules?

Answer 25

Any working circuit must be complete (closed) - all components are connected to make a loop so electrons can flow. Electrons flow from the negative terminal of a battery, through the circuit and return to the positive terminal on the battery (negative → positive).

Question 26

What is a Cell?

Answer 26

A cell is a source consisting of a positive and negative terminal.

Question 27

What is a Battery?

Answer 27

A battery is a source consisting of multiple cells.

Question 28

What is a Short Circuit?

Answer 28

A short circuit is an electrical circuit that allows a current to travel along an unintended path with no or very low electrical impedance. This results in an excessive current flowing through the circuit.

Question 29

What is Kirchoff’s Law?

Answer 29

Current and voltage behave differently depending on the circuit setup. Assume that wires do not use any energy! Along every pathway the electrons can take, the voltage provided by the source must all get used by the loads on that path.

Question 30

What is the difference in current and voltage in parallel vs. in series?

Answer 30

Current in parallel is all equal, but in series, all add up and are all different. Voltage in parallel all adds up, they are all different, and in series, they are all equal.

Question 31

What is Resistance in a series circuit?

Answer 31

In a series circuit, all electrons will pass through each resistor in that circuit. Therefore the total resistance experienced by the electrons is equal to the sum of the resistors.

Question 32

What is the formula for parallel circuits?

Answer 32

1/r0 = 1/r1 + 1/r2 …

Question 33

What is the formula for series circuits?

Answer 33

r0 = r1 + r2 …

Question 34

What is Power?

Answer 34

Power is the rate at which energy is transferred, or transformed. A device with a higher power is able to convert electrical energy into another type of energy faster than a device with a lower power.

Question 35

What are the formulas to calculate Power?

Answer 35

P = E/t P = I x V

Question 36

What is Efficiency?

Answer 36

Sometimes, there is unwanted and wanted energy released from electrical energy. Unwanted is thermal energy, wanted is light energy. ## Footnote Efficiency percentage = wanted/total electrical energy.

Question 37

What is the Cost of Electricity?

Answer 37

Cost = price x energy.