Physics Circuit Symbols

Question 1

What does a cell provide to a circuit?

Answer 1

Electrical energy

The longer line on a cell symbol indicates the positive side.

Question 2

How is a battery defined?

Answer 2

A battery consists of two or more cells

A battery provides electrical energy to a circuit.

Question 3

What happens when current flows through a lamp?

Answer 3

It converts electrical energy to light energy

A lamp lights up when current is present.

Question 4

What is the function of a switch in a circuit?

Answer 4

It allows you to complete or break a circuit

A switch allows current to flow when closed.

Question 5

Fill in the blank: A cell shows the _______ side with a longer line.

Answer 5

Positive

Question 6

Fill in the blank: A battery provides _______ energy to a circuit.

Answer 6

Electrical

Question 7

True or False: A lamp lights up only when there is no current flowing through it.

Answer 7

False

Question 8

True or False: A switch can either allow or prevent current in a circuit.

Answer 8

True

Question 9

What is a resistor?

Answer 9

A resistor restricts the flow of current, which may be to protect other components.

Question 10

What is a variable resistor?

Answer 10

A variable resistor is a resistor whose resistance can be varied in the circuit.

It could be used as a dimmer switch.

Question 11

What does a voltmeter measure?

Answer 11

A voltmeter measures potential difference.

It must be placed in parallel to measure the difference in electrical potential between two points.

Question 12

What does an ammeter measure?

Answer 12

An ammeter measures current.

Must be placed in series to measure current flowing in a circuit.

Question 13

What is a LED?

Answer 13

A LED emits light when a current flows but only allows current to flow in one direction.

Requires less energy than a lamp.

Question 14

What does a motor do?

Answer 14

A motor converts electrical energy into kinetic energy by turning.

Question 15

What is the function of a microphone?

Answer 15

A microphone generates a voltage when sound reaches it. It converts sound energy into an electrical signal.

It is used in a telephone or an intercom.

Question 16

What does a loudspeaker do?

Answer 16

Converts electrical energy into sound energy.

Question 17

What is a photovoltaic cell?

Answer 17

Converts light energy to electrical energy, can be used as the power source in a circuit. More light will mean a greater p.d. across the cell.

Question 18

What is the purpose of a fuse?

Answer 18

A fuse is a safety device - the metal core will melt when too much current is flowing in the circuit.

Question 19

What does a diode do?

Answer 19

A diode allows current to flow through it in one direction only.

Question 20

What is a capacitor?

Answer 20

A device that stores electrical charge and can be used in timing circuits or in the flash of a camera.

Question 21

What happens to the resistance of a thermistor as temperature increases?

Answer 21

The resistance of a thermistor increases as the temperature increases.

Question 22

What is an LDR used for?

Answer 22

An LDR can be used to control a circuit; its resistance decreases as light increases.

Question 23

What is a relay?

Answer 23

An electronically operated switch used to protect operators from high currents by using a low current supply to switch on a high current/voltage supply.

Question 24

What is an NPN Transistor?

Answer 24

Acts as a switch when a voltage of 0.7 V is applied across the base and emitter.

Question 25

What is an N-Channel enhancement MOSFET Transistor?

Answer 25

Acts as a switch when a voltage of approximately 2 V is applied across the gate and the source.