Electricity GCSE

Question 1

cell/battery

Answer 1

Provides the circuit with a voltage

Question 2

Switch

Answer 2

Turns on/off circuit

Question 3

Fixed Resistor

Answer 3

Resistor limits flow of CURRENT. Resistance cannot be changed

Question 4

Variable resistor

Answer 4

A resistor with a slider that can change its resistance

Question 5

Thermistor

Answer 5

Resistor depends on temperature, as temperature increases, resistance decreases

Question 6

Light dependent resistor

Answer 6

Resistance depends on light intensity, as light intensity increases, resistance decreases

Question 7

Diode

Answer 7

Allows current to flow in one direction only

Question 8

Light-Emitting Diode

Answer 8

Diode which emits light as current passes through it

Question 9

Ammeter

Answer 9

Used to measure current in circuit

Question 10

Voltmeter

Answer 10

Used to measure voltage in a circuit

Question 11

What does a circuit require to work effectively

Answer 11

An energy source of PD

A complete circuit as a loop

Electrical components

Question 12

How is an ammeter connected to a circuit?

Answer 12

In SERIES

Question 13

How is a voltmeter connected to a circuit?

Answer 13

In PARALLEL to the component which’s voltage is being measured

Question 14

What is the direction of flow in a circuit?

Answer 14

From the POSITIVE to NEGATIVE terminal of the power supply

Question 15

What are some sources of PD?

Answer 15

Cells, batteries, electrical generators

Question 16

What is PD?

Answer 16

Energy transferred per unit of charge

V = E / Q

Question 17

What is current?

Answer 17

Rate of flow of electric charge

Question 18

What is the unit for charge?

Answer 18

Coulomb (c)

Question 19

What is the equation for Charge?

Answer 19

Q = IT

Question 20

What is convectional current?

Answer 20

The flow of positive charge from the POSITIVE TO NEGATIVE terminals of a cell

Question 21

What is special about current in a closed circuit?

Answer 21

Current is the same at every point of a closed series circuit

Question 22

What do resistors do?

Answer 22

Resist current, the higher the resistor the lower the current.

Good conductors have low resistance, bad conductors have high resistance

Question 23

What is the unit for resistance?

Answer 23

Ω

1 volt per amp

Question 24

What does the current through a component depend on?

Answer 24

• Resistance of component

- Potential difference across component

Question 25

Equation for voltage

Answer 25

V = IR

Question 26

Required Practical for Resistance

Answer 26

Measuring how resistance changes as length of wire changes - Length of wire is directly proportional to the resistance Errors - Systematic (Crocodile clips could have not started on 0. Ammeter and Voltmeter could be faulty) - Random (current could have NOT been turned off, so temp of wire increased affecting precision) Safety considerations - - High current means high temperature, so wire could be hot - No liquids close to the experiment

Question 27

What is Ohms law?

Answer 27

The current through a conductor is DIRECTLY PROPORTIONAL to the potential difference across it. ONLY RELEVENT AT CONSTANT TEMPERATURES V = IR Ohmic conductors are conductors that obey this law

Question 28

What is special about a filament lamp (ohms law)?

Answer 28

- Non Ohmic conductor - Because resistance of lamp increases as temperature of lamp increases - Temp increases because of higher current

Question 29

Why does temp increase as current increases in a filament lamp?

Answer 29

- As current increases, temp increases - So the fixed atoms of the lamp vibrate more - Causing an increase in resistance because electrons find it harder to pass through - Causing the current to increase at a SLOWER RATE

Question 30

Linear Electrical Components

Answer 30

- Fixed resistors - Wires - Heating elements

Question 31

Non-Linear Electrical Components

Answer 31

- Filament lamps - Diodes & LEDs - LDRs - Thermistors

Question 32

How can thermistors be used

Answer 32

- Ovens - Fridges - Thermometers - Fire alarms

Question 33

How can LDRs be used?

Answer 33

- Alarm clocks | - Security lights

Question 34

Characteristics of a Series Circuit

Answer 34

- Current is same at all points - Total PD is shared between components - Total resistance is sum of all resistors

Question 35

Characteristics of a Parallel Circuit

Answer 35

- Total current through whole circuit is SUM of the currents through the separate branches - PD across each component is the same - Total resistance of two resistors is less than the resistance of the smallest individual resistor

Question 36

What is static electricity?

Answer 36

- Where two electrically insulating materials are rubbed against each other - And electrons are transferred from one to the other