Current, Potential Difference & Resistance Practice Questions

Complete the table.

State where the protons and neutrons are found in an atom.

Name the component represented by each symbol.

In the space below, draw the circuit symbol for a battery of two cells.

State how the ammeter must be connected in this circuit and explain why.

State how the voltmeter must be connected.

The voltmeter reading is $3.0\ \mathrm{V}$. State what this tells you about the energy transferred in the lamp.

Which statement describes the electric current in a metal wire?

A the flow of protons through the wire

B the rate of flow of charge through the wire

C the energy transferred per coulomb of charge

D the resistance of the wire per second

The current in the element of a hair dryer is $3.0\ \mathrm{A}$.

Calculate the charge that flows through the element in $45\ \mathrm{s}$.

charge = ............................................... C

State what is meant by the electric current in the LED.

The current in the LED is $25\ \mathrm{mA}$.

The LED is switched on for $5.0$ minutes.

Calculate the charge that flows through the LED in this time.

charge = ............................................... C

Calculate the resistance of the resistor.

resistance = ............................................... $\Omega$

The resistor is now replaced by one of resistance $15\ \Omega$. The battery is unchanged.

Calculate the new current in the circuit.

current = ............................................... A

In the space below, draw a circuit diagram of a circuit the technician could use.

Your circuit must include a cell (or battery), the fixed resistor, a variable resistor, an ammeter and a voltmeter.

The technician increases the resistance of the variable resistor.

Explain the effect this has on the reading on the ammeter.

Explain what is meant by an electric current in the copper wires.

Explain why there is a current in the torch when the switch is closed, but not when the switch is open.

Calculate the value of resistance that is missing from Figure 8.

resistance = ............................................... $\Omega$

Predict the current in the wire when the potential difference across it is $2.0\ \mathrm{V}$.

Use information from Figure 8.

current = ............................................... A

State the reading on ammeter $A_3$.

reading = ............................................... A

Calculate the charge that flows through the lamp in $2.0$ minutes.

charge = ............................................... C

The potential difference across the resistor is $6.0\ \mathrm{V}$.

Calculate the resistance of the resistor.

resistance = ............................................... $\Omega$

A student is given a $6\ \mathrm{V}$ battery, an ammeter, a voltmeter, connecting wires, a switch and a set of fixed resistors of known resistance.

Explain, with the aid of a circuit diagram, a method the student could use to investigate how the current in the circuit depends on the resistance in the circuit.

Show that the total charge the fully charged battery can deliver is about $7000\ \mathrm{C}$.

The speaker is used so that the current from the battery is $150\ \mathrm{mA}$.

Calculate, in hours, the time the fully charged battery will last.

time = ............................................... hours

When the current is $150\ \mathrm{mA}$ the potential difference across the speaker is $3.7\ \mathrm{V}$.

Calculate the resistance of the speaker.

resistance = ............................................... $\Omega$