Electric Circuit Components

Question 1

Junction of conductors

Answer 1

Allows an electric current to split at a junction

Resistance is typically low as it is a conductor, increases as temperature increases

Question 2

Conductors crossing (no connection)

Answer 2

Allows an electric current to flow in a circuit

Typically low resistance

Question 3

Switch

Answer 3

Turns an electric current on and off

Low resistance when the switch is closed and very high when open because of the air gap

Question 4

Cell

Answer 4

Provides the circuit with a source of energy or e.m.f

Will either be described as ‘negligible’ or will have low internal resistance

Question 5

Battery- two or more cells

Answer 5

Provides a circuit with a source of energy or e.m.f

Internal resistance will increase as more cells are added in series

Question 6

Terminals

Answer 6

Provides a circuit with a source of energy or an e.m.f

Low resistance

Question 7

Lamp

Answer 7

Transfers electrical energy to light energy as a useful form

Resistance will increase as the current increases

Question 8

Fixed resistor

Answer 8

Controls the amount of electric current flowing in a circuit or through a component
The resistance is fixed and dependent on the material that the resistor is made from- they are normally made from semi-conductors

Question 9

Variable resistor

Answer 9

Controls the amount of electric current flowing in a circuit or through a component
Resistance changes depending on the setting of the slider or dial

Question 10

Fuse

Answer 10

Safety device- will ‘melt’ or ‘blow’ if the current gets too high
Typically low and dependent on the length and thickness of the fuse wire and the material from which it’s made

Question 11

Heater

Answer 11

Transfers electrical energy into thermal energy as a useful form
Typically high resistance

Question 12

Ammeter

Answer 12

Measures the amount of electrical current flowing in a circuit or through an electrical component
Resistance is very low

Question 13

Voltmeter

Answer 13

Measures the size of the potential difference (e.m.f) across an electrical component
Resistance is very high

Question 14

Thermistor

Answer 14

Responds to the temperature of the environment and changes its resistance as a consequence
Resistance changes in response to the temperature of its surroundings

Question 15

Diode

Answer 15

Enables a current to flow in only one direction, often used to protect delicate components from having large currents flow through them
Resistance low in the forward bias arrangement, very high in the reverse bias arrangement

Question 16

Light-emitting diode (LED)

Answer 16

Like a diode, allows electrical current to flow through it in only one direction, when current flows through it it emits light
Resistance low in the forward bias arrangement, high in the reverse bias arrangement

Question 17

Light-dependent resistor (LDR)

Answer 17

Changes the current flowing in a circuit or through a component when the light intensity levels change
Resistance decreases as the light intensity increases