Electricity

Question 1

How do things get an electrical charge?

Answer 1

By transferring electrons from on substance to another. Gentle friction is enough. The result is a positively charged and a negatively charged substance

Question 2

What are conductors?

Answer 2

Electrons jump from one atom to another easily, readily flows through the substance. This is a conductor.

Question 3

What are insulators?

Answer 3

Electrons cannot flow easily. Can be charged with static electricity, but won’t allow a flow of electrons.

Question 4

Examples of conductors

Answer 4

Metals, Graphites, Salt water

Question 5

Examples of insulators

Answer 5

Plastic, glass, wood, air, pure water

Question 6

What’s an energy converter?

Answer 6

Something the electrons go through with resistance such as a lightbulb, heater or motor.

Question 7

What are electrostatic forces?

Answer 7

Forces caused by 2 electrically charged objects acting across an electric field. Can be attractive or repulsive.
A push or a pull between two charged substances.

Question 8

What’s electricity?

Answer 8

The flow of electrons. As these electrons hit objects, they are able to do things to them.

Question 9

What are the 3 main concepts?

Answer 9

Current, Voltage, Resistance

Question 10

What’s current?

Answer 10

How much charge ( how many electrons)are flowing past a point per second.

Question 11

What’s voltage?

Answer 11

Energy each electron has. Can be provided by a battery.

Question 12

What’s resistance?

Answer 12

How much the objects in the circuit (for example the material in the wire, or a light-bulb) resist the motion of these electrons.

Question 13

Symbol and Unit for Current

Answer 13

Amperes (I)

Question 14

Symbol and Unit for Voltage

Answer 14

Volts (V)

Question 15

Symbol and Unit for Resistance

Answer 15

Ohms (R) Ω

Question 16

What’s a series circuit?

Answer 16

• closed circuit
• not common in homes
• unreliable wiring method
• failure effects all devices
• higher resistance, so lower current and power
• each device cannot be controlled independantly

Question 17

What’s a parrallel circuit?

Answer 17

• closed circuit
• common in homes
• reliable wiring method
• failure doesn’t effect all devices
• each device can be turned on or off independantly

Question 18

What measures current?

Answer 18

Ammetre

Question 19

What measures voltage?

Answer 19

Voltmetre

Question 20

What’s Ohms Law

Answer 20

Current = Voltage
———–
Resistance
I=V
—
R
I=Amps
V=Volts
R=Ohms

Question 21

What is power?

Answer 21

The amount of electrical energy converted per
second. Measured in “watts” (W).

Question 22

What are the types of current?

Answer 22

Alternating, Direct

Question 23

What happens in a direct current?

Answer 23

The electrical current produced by a battery
flows steadily from the -ve terminal to the
+ve terminal. The electrical field of a battery is constant and always points in the same direction.

Question 24

What happens in an alternating current?

Answer 24

The electrical field moves back-and-forth rapidly. Electrons do not flow steadily, but jump back-and-forth.

Question 25

Formula for electrical work?

Answer 25

Work done = force × distance

Question 26

Formula for charge?

Answer 26

Charge = current × time
Q = I x t

Question 27

What’s actual current?

Answer 27

Flows from negative terminal to positive (electrons).

Question 28

What’s conventional current?

Answer 28

Flows from positive terminal to negative (positive charge).