Physics: Electricity and Circuits Worksheet

Question 1

A simple circuit has a battery, wires, and one light bulb. Explain why the bulb lights only when the circuit is closed.

Accepted Answer

The bulb lights only when the circuit is closed because electric charge can flow in a complete path from one side of the battery, through the bulb, and back to the other side of the battery. If the path is broken, current cannot flow.

Question 2

Define electric current in your own words.

Accepted Answer

Electric current is the flow of electric charge through a material, such as a wire. It is measured in amperes, or amps.

Question 3

A circuit has a 9 volt battery and a 3 ohm resistor. Use Ohm's law, V = I × R, to find the current.

Accepted Answer

The current is 3 amperes because I = V ÷ R, so I = 9 volts ÷ 3 ohms = 3 amperes.

Question 4

Look at a circuit with two light bulbs connected one after the other in the same loop. Is this a series circuit or a parallel circuit? Explain.

Accepted Answer

This is a series circuit because the two light bulbs are connected along a single path. The same current must pass through one bulb and then the other.

Question 5

In a series circuit with two bulbs, one bulb burns out and creates an open gap. What happens to the other bulb? Explain why.

Accepted Answer

The other bulb goes out because the burned-out bulb creates a break in the only path for current. In a series circuit, all parts depend on the same complete loop.

Question 6

In a parallel circuit, two bulbs are connected on separate branches. One bulb burns out. What happens to the other bulb? Explain why.

Accepted Answer

The other bulb can stay lit because it is on a separate branch that still provides a complete path for current. A parallel circuit has more than one path for current to flow.

Question 7

A student builds a circuit with a battery, a switch, wires, and a buzzer. What is the purpose of the switch?

Accepted Answer

The switch controls whether the circuit is open or closed. When the switch is closed, current can flow and the buzzer can work. When the switch is open, current cannot flow.

Question 8

Classify each material as a conductor or an insulator: copper wire, rubber, aluminum foil, plastic spoon.

Accepted Answer

Copper wire and aluminum foil are conductors because they allow electric charge to flow easily. Rubber and a plastic spoon are insulators because they do not allow charge to flow easily.

Question 9

A circuit has a current of 2 amperes flowing through a 5 ohm resistor. Use Ohm's law to find the voltage across the resistor.

Accepted Answer

The voltage is 10 volts because V = I × R, so V = 2 amperes × 5 ohms = 10 volts.

Question 10

Two circuits each use the same battery and identical bulbs. Circuit A has one bulb. Circuit B has three identical bulbs in series. Which circuit's bulbs will usually be dimmer? Explain.

Accepted Answer

The bulbs in Circuit B will usually be dimmer because adding bulbs in series increases the total resistance. More resistance reduces the current, so each bulb gets less electrical energy per second.

Question 11

A resistor has a voltage of 12 volts across it and a current of 4 amperes through it. What is its resistance?

Accepted Answer

The resistance is 3 ohms because R = V ÷ I, so R = 12 volts ÷ 4 amperes = 3 ohms.

Question 12

Explain the difference between voltage and current.

Accepted Answer

Voltage is the electric potential difference that pushes electric charges through a circuit. Current is the rate at which electric charge flows through the circuit.

Question 13

A diagram shows a battery connected to a bulb, but one wire is not attached to the battery terminal. Will the bulb light? Explain.

Accepted Answer

The bulb will not light because the circuit is open. The loose wire creates a break in the path, so current cannot flow through the bulb.

Question 14

A student says, 'Batteries create electrons that flow through wires.' Correct this statement using what you know about circuits.

Accepted Answer

Batteries do not create the electrons in the wires. A battery provides a voltage that pushes charges already present in the circuit, causing them to flow when the circuit is closed.

Question 15

A circuit has a battery, a switch, and two bulbs connected in parallel. Draw or describe the path current can take when the switch is closed.

Accepted Answer

When the switch is closed, current can leave the battery and split into two separate branches, with one branch going through each bulb. The branches then join again and return to the other side of the battery.

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Physics: Electricity and Circuits

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