Circuits – current and voltage in series and parallel

Question 1

recognise

• Recognise common circuit symbols.

Answer 1

charge = q
time in seconds = s
amps or amperes = I
unit for charge is coulomb = C

Question 2

recall

• Recall what is required for a complete circuit.

Answer 2

In order to have a complete circuit there must be at least a power source, wires and a load. The wires are connected to each pole of the power source and then to the proper poles of the load.

Question 3

define

• Define electric current.

Answer 3

current is the rate at which electrons flow pas a at a point in an complete electrocal circuit

Question 4

define

• Define conventional current.

Answer 4

conventional current is a direction of flow of positively charged particles.

Question 5

recall

• Recall common energy transformations in circuits.

Answer 5

When it is connected to a complete circuit, electrons move and energy is transferred from the battery to the components of the circuit. Most energy is transferred to the light globe (or other energy user) where it is transformed to heat and light or some other form of energy.

Question 6

define

• Define voltage.

Answer 6

Voltage is the force that makes electrons flow. It’s a difference in potential energy between two different points in a circuit.

Question 7

descirbe

• Describe and explain how current behaves in series and parallel circuits.

Answer 7

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 8

describe

• describe and explain how voltage behaves in series and parallel circuits.

Answer 8

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 9

explain

• Explain how to change voltage.

Answer 9

There are many ways to change a voltage. You could use a power supply that accepts one voltage and outputs another.

Question 10

distinguish

• Distinguish between cells and batteries.

Answer 10

A cell is a single unit of device that converts chemical energy into electrical energy. A battery is a collection of cells that converts chemical energy into electrical energy.

Question 11

describe

• Describe how to measure current in series and parallel circuits using an ammeter.

Answer 11

The most common way to measure current in a circuit is to break the circuit open and insert an “ammeter” in series (in-line) with the circuit so that all electrons flowing through the circuit also have to go through the meter.

Question 12

describe

• Describe how to measure voltage in series and parallel circuits using a voltmeter.

Answer 12

A voltmeter is placed in parallel with the voltage source to receive full voltage and must have a large resistance to limit its effect on the circuit. An ammeter is placed in series to get the full current flowing through a branch and must have a small resistance to limit its effect on the circuit.

Question 13

recall

• Recall half-cell reactions in batteries.

Answer 13

A half cell is one of the two electrodes in a galvanic cell or simple battery. For example, in the Zn−Cu battery, the two half cells make an oxidizing-reducing couple. Placing a piece of reactant in an electrolyte solution makes a half cell.