Electricity and Magnetism

Question 1

What are the two kinds of electricity?

Answer 1

Static and conventional.

Question 2

How many subatomic particles are mobile and can therefore transfer energy?

Answer 2

One: the electron.

Question 3

What is static electricity? what is it caused by?

Answer 3

Static electricity is electricity that can neither move nor flow. It is caused by a build-up of electrons due to friction between insulators; as they cannot conduct, there is no movement and the electricity is static.

Question 4

How can an object be made to be charged with static electricity?

Answer 4

Rub two insulating materials against each other. This friction will transfer electrons from the stationary object to the one rubbing. This will negatively charge the object, which will repel other electrons and expose the positive nucleus in an object’s atoms. The two objects will appear to ‘stick’ together.

Question 5

What is the law of static attraction and repulsion?

Answer 5

Opposite electrical charges attract, like/similar electrical charges repel.

Question 6

What are the symbols for the four kinds of switch? a motor? a lamp/bulb? a buzzer? a cell? a battery? a (variable) resistor? a wire? an ammeter? a voltmeter? crocodile clips? an ohmmeter? an LED?

Answer 6

Refer to physical flashcard.

Question 7

What are the ways to connect components? how many are there?

Answer 7

Two.

Series (end-to-end) and parallel (side-by-side).

Question 8

How are voltmeters connected in a circuit?

Answer 8

In parallel.

Question 9

How are ammeters connected in a circuit?

Answer 9

In series.

Question 10

What is a conducting material? Give some examples.

Answer 10

A material that will conduct electricity well and allow it to flow.
Most metals.
Most alloys.
Graphite and graphene.
Water (incl. wet wood, etc.).

Question 11

What is an insulating material? Give some examples.

Answer 11

A material that will not conduct electricity well.
Glass.
String.
Paper.
Plastic.
Wood.
Elastic.
Bronze (most alloys will conduct).
Ceramics.
Clay.
Cardboard.

Question 12

Are conductors mostly metals or non-metals? why?

Answer 12

Metals. Metals have approximately one electron per atom, which are termed free electrons. They are free to move and create electricity.

Question 13

What is the symbol for current?

Answer 13

I.

Question 14

What is current measured in? what is its symbol? what is the instrument used to measure these units?

Answer 14

Amp(ere)s (A). Ammeter.

Question 15

What is the symbol for voltage?

Answer 15

V.

Question 16

What is voltage measured in? what is its symbol? what is the instrument that measures these units?

Answer 16

Volts (V). Voltmeter.

Question 17

What two concepts is current defined using?

Answer 17

Charge (a group of electrons) and time.

Question 18

What is the definition of current?

Answer 18

The amount of charge flowing past a point in a given time.

Question 19

What is the symbol for the rate of flow of charge?

Answer 19

H.

Question 20

Does all the current that leaves the battery return to the battery?

Answer 20

Yes.

Question 21

Is current the same or different at different points in a series circuit?

Answer 21

The same at all points.

Question 22

Is current the same or different at different points in a parallel circuit?

Answer 22

The circuit will split according to the resistance of each section.

Question 23

What two concepts is voltage defined using?

Answer 23

Charge (a group of electrons) and energy (a measure of an object’s ability to do work).

Question 24

What is the definition of voltage?

Answer 24

The amount of energy lost or gained by a unit of charge.

Question 25

Is voltage the same or different at different points in a series circuit?

Answer 25

Different — it is divided between components.

Question 26

Is voltage the same or different at different points in a parallel circuit?

Answer 26

The same across all pathways.

Question 27

What is the definition of resistance?

Answer 27

A measure of the amount of opposition to the flow of current.

Question 28

Do all circuit parts have a resistance?

Answer 28

Yes — some have a greater resistance (e.g. bulbs/resistors) as the flow of current is more restricted, while others have less resistance (e.g. wires) as the current flows easily.

Question 29

What is Ohm’s Law in words?

Answer 29

At constant temp., the I through a wire is directly proportional to the applied V.

Question 30

What is the unit of resistance? what is its symbol? what instrument is used to measure these units?

Answer 30

Ohm (uppercase omega letter). Ohmmeter.

Question 31

What is Ohm’s Law as a formula?

Answer 31

R = V/I.
V = IR.
I = V/R.

Question 32

How is the combined resistance of resistors in series calculated?

Answer 32

Add the resistances of all the resistors together.

Question 33

How is the combined resistance of equal resistors in parallel calculated?

Answer 33

The ‘product over sum’ rule (RR/R + R) or R/2.

Question 34

How is the combined resistance of unequal resistors in parallel calculated?

Answer 34

The ‘product over sum’ rule (RR/R + R).

Question 35

Does all the voltage that leaves the battery return to the battery?

Answer 35

No — all the voltage gained at the battery/cell is lost in the rest of circuit.

Question 36

How will length affect the resistance of a wire?

Answer 36

There will be more resistance if longer, and vice versa.

Question 37

How will cross-sectional area affect resistance of a wire?

Answer 37

Cross-sectional area is similar to width. A greater cross-sectional area will result in less resistance, and vice versa.

Question 38

How will the material affect resistance of a wire?

Answer 38

Different materials have different resistances.

Question 39

How will temperature affect resistance of a wire?

Answer 39

A greater temp. results in a greater resistance, and vice versa.