2. Electricity (current and circuit symbols, IV characteristics)

Question 1

What is current?

Answer 1

It is the flow of electrical charge (electrons)

Question 2

What is voltage?

Answer 2

The driving force that pushes the electrons

Question 3

What is resistance?

Answer 3

It slows down the flow of current

Question 4

What is the equation for finding charge flow?

Answer 4

Q = IT
Charge (C) = current (A) x time (s)

Question 5

What is charge flow measured in?

Answer 5

Coulombs (C)

Question 6

What is current measured in?

Answer 6

Amps (A)

Question 7

What is time measured in?

Answer 7

Seconds (S)

Question 8

What circuit symbol is this and what does it do?

Answer 8

A cell - which pushes electrons from the negative to positive terminal

Question 9

What circuit symbol is this and what does it do?

Answer 9

A switch - when closed it allows current to flow through

Question 10

What circuit symbol is this and what does it do?

Answer 10

A filament bulb - it emits light when current passes through it

Question 11

What circuit symbol is this and what does it do?

Answer 11

A diode - it only allows current to flow in one direction

Question 12

What circuit symbol is this and what does it do?

Answer 12

A light emmiting diode (LED) - it emits light

Question 13

What circuit symbol is this and what does it do?

Answer 13

An ammeter - it measures the current

Question 14

What circuit symbol is this and what does it do?

Answer 14

A fixed resistor - it limits the current which flows through the circuit

Question 15

What circuit symbol is this and what does it do?

Answer 15

A variable resistor - you change the resistance so varies the current flowing through it

Question 16

What circuit symbol is this and what does it do?

Answer 16

A fuse - it is a circuit break, as if the current is too high, the wire (inside the box) will melt

Question 17

What circuit symbol is this and what does it do?

Answer 17

A thermistor - it transfers electrical energy to heat

Question 18

What circuit symbol is this and what does it do?

Answer 18

A voltmeter - it measures the voltage flowing through a circuit

Question 19

What circuit symbol is this and what does it do?

Answer 19

A light dependent resistor (LDR) - it measures the light intensity

Question 20

What is the equation for potential difference?

Answer 20

V = IR
potential difference (V) = current (A) x Resistance (ohms)

Question 21

What is a super conductor?

Answer 21

A material that conducts electricty with very little resistance at a very low temperature

Question 22

What are the factors affecting resistance?

Answer 22

• temperature
• length of wire
• diameter of wire

Question 23

How does temperature affect resistance?

Answer 23

As temperature increases, resistance increases

Question 24

What are IV characteristics?

Answer 24

Characteristics of voltage and current

Question 25

What are the IV characteristics for an Ohmic conductor?

Answer 25

Current and voltage are directly proportional to one another

Question 26

What are the IV characteristics for a Filament bulb?

Answer 26

As current increases, temperature increases, this increases the resistance, so less current is able to flow through

Question 27

What are the IV characteristics for a Diode?

Answer 27

It only allows current to flow in one direction and in the other direction there is a very high resistance

Question 28

Which component is the IV characteristics graph showing for?

Answer 28

An ohmic conductor

Question 29

Which component is the IV characteristics graph showing for?

Answer 29

A filament bulb

Question 30

Which component is the IV characteristics graph showing for?

Answer 30

A diode