P4 Electric Circuits

Question 1

What is a circuit diagram?

Answer 1

A diagram that shows how the components in a circuit are connected together

Each component in a circuit diagram has its own symbol.

Question 2

What is the difference between a battery and a cell?

Answer 2

A cell is a single unit that provides electric power, while a battery consists of two or more cells connected together.

Question 3

What determines the size of an electric current?

Answer 3

The rate of flow of electric charge.

Question 4

How do you calculate the size of an electric current?

Answer 4

Current (I) = Charge flow (Q) / Time taken (t)

Charge flow is measured in coulombs (C) and time in seconds (s).

Question 5

What is an electric current?

Answer 5

A flow of charge.

Question 6

What is the unit of electric charge?

Answer 6

Coulombs (C).

Question 7

What is the unit of electric current?

Answer 7

Amperes (A), sometimes abbreviated as amps.

Question 8

What is the relationship between amperes and coulombs?

Answer 8

1 ampere = 1 coulomb per second.

Question 9

What is the function of a switch in a circuit?

Answer 9

To enable the current in a circuit to be switched on or off.

Question 10

What does a diode do?

Answer 10

Allows current to pass through in one direction only.

Question 11

What is a variable resistor used for?

Answer 11

To vary the amount of current flowing through a circuit.

Question 12

What is a fuse designed to do?

Answer 12

Melt and break the circuit if the current exceeds a certain amount.

Question 13

Fill in the blank: An _______ is used to measure electric current.

Answer 13

ammeter

Question 14

Fill in the blank: A _______ is used to measure potential difference.

Answer 14

voltmeter

Question 15

What happens to the current in a single closed loop circuit?

Answer 15

The current at any point is the same as at any other point in the circuit.

Question 16

What does an electric heater do?

Answer 16

Transfers energy from an electric current to heat the surroundings.

Question 17

What is the equation for electric current?

Answer 17

I = Q / t

Question 18

True or False: The direction of current is shown from positive to negative in a circuit.

Answer 18

True

Question 19

What is the purpose of an indicator in a circuit?

Answer 19

To emit light as a signal when a current passes through it.

Question 20

Describe the energy transfers of an electron in a circuit when the switch is closed.

Answer 20

Electrons transfer energy from the power source to the load (e.g., a bulb) as they flow through the circuit.

Question 21

What happens to the brightness of a bulb when a variable resistor is adjusted?

Answer 21

The brightness changes depending on the amount of current flowing through the bulb.

Question 22

Calculate the current if a charge of 16.0 C passes through a bulb in 5.0 seconds.

Answer 22

3.2 A