Electricity

Question 1

What is a current?

Answer 1

An electric current is a rate of flow of charge. Electric current is measured in amps (A). In electric circuits it is the negatively charged electrons that flow. Conventional current flows in the opposite direction.

Question 2

What is voltage?

Answer 2

Voltage is a measure of energy in an electrical circuit; its the electrical push from the battery. Being more precise, voltage is a measure of the amount of energy given to each unit of charge pushed out by the battery. Voltage is measured in volts (V).

Question 3

How does a battery and cell differ?

Answer 3

A battery is made up of 2 or more cells.

Question 4

What is the energy transfer in a bulb?

Answer 4

Electrical energy to heat energy and light energy.

Question 5

What element are most wires made of and why?

Answer 5

Copper is most common as it is a conductor so it works in a circuit.

Question 6

What does an ammeter measure?

Answer 6

Current in Amps (A)

Question 7

What does a voltmeter measure and what are the units?

Answer 7

Voltage in Volts (V)

Question 8

What is the main job of a diode?

Answer 8

Allows a current to flow in one direction.

Question 9

What is the energy transfer in a resistor?

Answer 9

Electrical energy is converted to heat energy

Question 10

What is the purpose of a variable resistor?

Answer 10

It adjusts the value of current voltage and changes the resistance in a circuit.

Question 11

When a current lights a bulb, what is flowing in the wires?

Answer 11

Electrons

Question 12

What is potential difference?

Answer 12

Potential difference is the energy transferred by each unit of charge for example: the difference in the amount of energy that charge carriers have between two points in a circuit.

Question 13

What is used to measure potential difference?

Answer 13

A voltmeter

Question 14

How does current and voltage behave in series and parallel circuits?

Answer 14

In a series circuit, the current through each of the components is the same, and the voltage across the circuit is the sum of the voltages across each component. In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component.

Question 15

What is resistance?

Answer 15

Resistance is a measure of how difficult it is for current to flow around a circuit. A higher resistance= a lower current.

Question 16

What is ohms law?

Answer 16

Potential Difference= Current x Resistance

                                    V=IxR

Question 17

Name an experiment you could do to work out the resistance using a voltmeter and an ammeter:

Answer 17

Set up an ammeter somewhere in the series circuit; this will give you the amount of current flowing in the circuit. Next set up a voltmeter in parallel to the object, in this case a light bulb, to find the potential difference across it. Using the equation R = V/I , we can find the resistance.

Question 18

What is the unit of resistance?

Answer 18

Ohms