Basic Electricity

Question 1

Define the term “Electricity”?

Answer 1

Electricity is the presence or flow of charged particles.

Question 2

Explain “Electrostatic Force”?

Answer 2

Electrostatic force (also called Coulomb's law) is a force that operates between charges. 
It states that charges of the same type repel each other, while charges of opposite types are attracted together.

Question 3

Explain how electric current is created?

Answer 3

A free electron is floating in a space between atoms, it’s pulled and prodded by surrounding charges in that space.

In this chaos the free electron eventually finds a new atom to latch on to; in doing so, the negative charge of that electron ejects another valence electron from the atom. Now a new electron is drifting through free space looking to do the same thing.

This chain effect can continue on and on to create a flow of electrons called electric current.

Question 4

State three good conductors of electricity?

Answer 4

• Copper
• Silver
• Gold

Question 5

State three good insulators?

Answer 5

• Glass
• Rubber
• Plastic

Question 6

What four components are required to form an electrical circuit?

Answer 6

• An energy source (AC or DC)
• A conductor (wire),
• An electrical load (device), and
• At least one controller (switch).

Question 7

All electrical circuits consist of three sperate but very much related electrical quantities, what are these?

Answer 7

• Voltage, (v )
• Current, ( I )
• Resistance, (Ω).

Question 8

State the four factors that affect resistance?

Answer 8

• Material: Copper has lower resistance than steel.
• Length: The longer the wire, the greater the resistance.
• Thickness: Smaller diameter wires have greater resistance.
• Temperature: For most materials, the hotter the material the greater it’s resistance

Question 9

What is the unit of measurement for electrical current?

Answer 9

An ampere (AM-pir), or amp, is the international unit used for measuring current.

Question 10

What are the two different types of current?

Answer 10

• Alternating Current

* Direct Current

Question 11

Which type of current is required to produce radio waves?

Answer 11

Transmitter antennas use Alternating Current to produce Radio Waves.

Question 12

What is the relationship between Voltage and Current?

Answer 12

Proportional

• An increase in voltage will increase the current
• A decrease in voltage will decrease current
• This gives us the rule that voltage and current are:

Question 13

What is the relationship between Current and Resistance?

Answer 13

Inversely Proportional

• An increase in resistance, will reduce the current.
• A decrease in resistance, allows the current to increase back to its original amount.
• This gives us the rule that Current and Resistance are:

Question 14

What formula can be used to calculate the relationships between Voltage, Current and Resistance?

Answer 14

V 	= 	Voltage (V)
I	=	Current (A)
R	=	Resistance (Ω)	

Triangle.

Question 15

State three applications where Direct Current would be utilised?

Answer 15

• Mobile Phones
• Flashlights
• Hybrid and Electric Vehicles

Question 16

Define the term “Alternating Current”?

Answer 16

Is an electric current which periodically reverses direction.

Question 17

Calculate the resistance of a bulb, if the current is 0.5A and the potential difference across the bulb is 2V?

Answer 17

2V / 0.5A = 4Ω

Question 18

Calculate the potential difference across a bulb if the resistance is 3Ω and the current flowing is 2A?

Answer 18

2A x 3Ω = 6V

Question 19

What is the voltage required to create a 20A current if the resistance is 4Ω?

Answer 19

80V / 4Ω = 20A

Question 20

What are the two different types of circuits?

Answer 20

• Series Circuit

- Parallel Circuit