SP6a Electricity and circuits

Question 1

What do atoms contain?

Answer 1

.protons +
.neutrons 0
.electrons -

.electron shell
.nucleus

Question 2

Current?

Answer 2

the rate of flow of electric charge. It is not used up.

Question 3

When will current flow? (2)

Answer 3

.there is a power supply
.a complete circuit

Question 4

Conventional current flow?

Answer 4

flows from the positive terminal of the battery to the negative terminal.

Question 5

Electron flow?

Answer 5

flows from negative terminal of the battery to the positive terminal.

Question 6

What does a chemical reaction in the battery do?

Answer 6

gives one end of the battery a small positive charge. The other end of the battery is given a small negative charge.

Question 7

What happens before the switch is turned on?

Answer 7

before the switch is turned on there are charges in the battery. There are charges through all the wires and in the lamp too.

Question 8

What happens after the switch is turned on?

Answer 8

when the switch is turned on, the battery forces the charges in the wires and the lamp to move.

Question 9

In the wires, where are charges pushed from and towards?

Answer 9

charges are pushed from one end of the battery, and pulled towards the other end.

Question 10

What is the flow of charge in a circuit called?

Answer 10

electric current.

Question 11

What is electric current measured in and how is it measured?

Answer 11

it is measured in amperes (A), using an ammeter, connected in series to measure the current passing through a component.

Question 12

What is the voltage across a component equal to?

Answer 12

the work done per unit charge.

Question 13

In a circuit, what is the voltage across the power supply always equal to?

Answer 13

the sum of the rest of the voltages across the rest of the components.

Question 14

Diffference between series and parallel circuit in relation to voltage.

Answer 14

.series circuit - components divide the available voltage between them
.parallel circuit - components have equal voltage

Question 15

What is potential difference measured in and how is it measured?

Answer 15

it is measured in volts (V), using a voltmeter, connected in parallel to measure the potential difference across a component.

Question 16

State differences between parallel and series in relation to potential difference and current.

Answer 16

.parallel - potential difference across components is the same
.series - potential difference is shared between components

.parallel - current at a junction splits
.series - components have the same current

Question 17

State 3 differences between series and parallel.

Answer 17

.series - one lamp breaks then all the lamps go out
.parallel - one lamp breaks then the others stay on

.series - lamps cannot be switched on and off imdependently
.parallel - lamps in one branch can be switched on and off independently

.series - adding more lamps makes them get dimmer
.parallel - as more lamps are added the brightness stays the same

Question 18

State 2 similarities between series and parallel.

Answer 18

.voltage pushes free electrons
.electrons flow from negative to positive terminal