Electricity

Question 1

Electrical charge:
1. Neutrons have __ and are in the___
2. Protons have a__ and are in the___
3. Electrons have a__ and are in the___

Answer 1

1. no charge (neutral) in the nucleus
2. positive charge in the nucleus
3. negative charge in the orbital shells

Question 2

In a metal wire when no electricity is supplied, in which way do the metal atoms move?

Answer 2

Metal atoms (such as Copper) are surrounded by a ‘sea’ of free electrons which can move between atoms.

Question 3

When current is supplied how are the electrons moving?

Answer 3

the free electrons all move away
from the negative region towards the positive region.

Question 4

What are conductors and insulators

Answer 4

conductors:
are materials (usually solid
metals) which allow electricity to flow
through with low resistance.

insulators:
are materials (usually solid non-
metals) which do not allow electricity to flow through (they have high resistance).

Question 5

what is an electric circuit

Answer 5

Electricity which travels in a path is
described as an electric circuit.

Question 6

What do all circuits require

Answer 6

an energy source (a cell)

Question 7

Electricity will only flow through if there is an___ path

Answer 7

completely unbroken path

Question 8

What is a Series Circuit?

Answer 8

● All components of
the circuit are
connected to form
a single loop.

Question 9

Series circuits are easy to connect but are not very practical because:

Answer 9

1) Globes cannot be controlled individually. A switch would
turn them all on or off

2) Current stops flowing if any of the globes ‘blow’. This breaks the circuit and all other globes will go out

3) Adding more globes to the circuit makes them glow duller
than before

Question 10

What is a Parallel Circuit

Answer 10

A parallel circuit has
a number of branching
circuits with each
branch having its own
components.
There is more than one
path for the current
to take.

Question 11

Parallel circuits have many advantages over series circuits:

Answer 11

1) Each branch can have its own switch to allow globes to be turned on and off independently

2) Only one branch is affected if a globe blows

3) Adding extra globes does not affect their brightness

Question 12

Series circuits:

Components in a _____have the same ___ through them but split the ___ between them

Answer 12

series circuit
current
voltage

Question 13

Parallel circuit

Components in a ____ have the same ___ across them but split the ____ between them

Answer 13

parallel circuit
voltage
current

Question 14

What is current?

Answer 14

The rate at which charge (electrons) flows through a circuit.

Question 15

What does an ammeter measure?

Answer 15

the electric current that flows through a circuit every second.

Question 16

Electric current is measured in

Answer 16

amperes or amps (A)

Question 17

Voltage (Potential difference)

Answer 17

● The difference in electrical potential energy between two points.

it is the push

Question 18

Resistance

Answer 18

● Anything in a circuit that uses
(transfers/transforms) energy in a circuit.

Question 19

what does the resistance measure

Answer 19

how difficult it is for electrons to flow through a material or component as they collide with metal ions.

Question 20

Electric resistance is in

Answer 20

ohms ().

Question 21

ohms is _____
rather than measured.

Answer 21

calculated

Question 22

The resistance current experiences may depend on:

Answer 22

○ Type of material the wire is made from (conductors are low in resistance, insulators are high)

○ Length of the wire. Doubling the length of a wire doubles the number of obstacles the electrons must pass through.

○ Thickness of the wire. It is more difficult for electrons to pass along thin wires than to pass along thick wires.

Question 23

formula for ohms law

Answer 23

Voltage = Current x Resistance
V= I*R
R=V/I
I=V/R