P16: Electricity

Question 1

Ion

Answer 1

A charged atom

Question 2

Rubbing a polythene rod with a dry cloth…

Answer 2

Transfers electrons to the surface atoms of rod from the cloth, so the rod becomes negatively charged.

Question 3

Rubbing a perspex rod with a dry cloth…

Answer 3

Transfers electrons from the surface atoms of the rod to the cloth, so the rod becomes positively charged.

Question 4

Answer 4

Battery.

A cell is necessary to push electrons around a complete circuit. A battery consists of two or more cells.

Question 5

Answer 5

Switch.

A switch enables the current in a circuit to be switched on or off.

Question 6

Answer 6

Indicator.

An indicator is designed to emit light as a signal when a current passes through it or as a light source such as a bulb.

Question 7

Answer 7

Ammeter.

Used to measure current.

Question 8

Answer 8

Resistor.

Limits the current in a circuit.

Question 9

Answer 9

Variable Resistor.

allows the current to be varied.

Question 10

Answer 10

Voltmeter.

Used to measure voltage.

Question 11

Answer 11

Diode

allows current through in one direction only.

Question 12

Answer 12

LED

Emits light when a current passes through it.

Question 13

Answer 13

Fuse

designed to melt and break the circuit if the current through it is greater than a certain amount.

Question 14

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LLLLLLLI

Answer 14

Heater.

Designed to transfer electrical energy to heat the surroundings.

Question 15

What way in a circuit does current flow?

Answer 15

+ to -

Question 16

The size of an electric current…

Answer 16

… is the rate of flow of an electric charge.

Question 17

What is the unit of electric charge?

Answer 17

Coulombs (C)

Question 18

Current =

Answer 18

Charge flow (C) / Time taken (s)

Question 19

Potential difference across the component (V) =

Answer 19

Energy transferred (J) / Charge (C)

Question 20

What causes resistance?

Answer 20

Electrons having to push past lots of vibrating ions in a metal filament.

Question 21

resistance (Ω) =

Answer 21

Voltage / Current

Question 22

Define Ohm’s Law

Answer 22

The current through a resistor at constant temperature is directly proportional to the voltage across the resistor.

Question 23

2 Non-Ohmic Conductors

Answer 23

Filament Bulb

Diode

Question 24

1 Ohmic Conductor

Answer 24

Resistor

Question 25

Answer 25

Thermistor

A resistor that depends on temperature.

Question 26

Answer 26

Light Dependent Resistor

A resistor that depends on the intensity of light.

Question 27

In a series circuit, how much current passes through each component?

Answer 27

The same amount.

Question 28

In a series circit, what happens to the voltage?

Answer 28

It is shared between all of the components.

Question 29

In a parallel circuit, what happens to the current?

Answer 29

It is split up, and runs through separate components.

Question 30

In parallel, what is the voltage like for each component?

Answer 30

the same.