electricity

Question 1

a cell

Answer 1

portable sources of electrical energy

Question 2

voltage written on the battery

Answer 2

tells us the amount of energy that can be transferred in the circuit.

Question 3

symbol for a cell

Answer 3

the long line and the short one

Question 4

Two or more cells working together are referred to as a

Answer 4

battery.

Question 5

voltage

Answer 5

chemical potential energy stored in a battery

Question 6

what do resistors do

Answer 6

resist the flow of current

Question 7

rheostat (variable resistor)

Answer 7

can be added to a circuit to adjust the resistance. The variations allow lights to be made dimmer or volume to be adjusted through a speaker.

Question 8

light dependent resistor (LDR)

Answer 8

is sensitive to the amount of light available and turns on when the amount of light drops to a specific level. It usually has high resistance in the dark and low resistance in the light.

Question 9

Diodes

Answer 9

are components in a circuit that control the flow of current in a particular direction. They are usually made of two semiconductors. The light emitting diode (LED) converts electrical energy to light energy and light sensitive diodes convert light energy to electrical energy.

Question 10

V =

Answer 10

I x R

Question 11

I =

Answer 11

V/R

Question 12

R =

Answer 12

V/I

Question 13

Safety practices

Problems with parallel connections?

Answer 13

Every branch in a parallel circuit receives the full potential difference (voltage) which means that in houses each branch receives 240V from the power grid. As the load increases in each branch so does the current which could result in an overload in a circuit. The wires can get too hot and a fire could start, this could also result in a short circuit as wires melt.

Question 14

what does a fuse look like in a circuit

Answer 14

rectangle with line through the middle of the length

Question 15

3 wires in a plug?

Answer 15

live wire
earth wire
neutral wire

Question 16

adv vs disadvantages of wind powered energy in fish hoek

Answer 16

advantages
Can be found singularly (alth. used in groups large scale)
Potentially infinite energy supply.
lots of wind in FH
disadvantages
costly.
ugly

Question 17

adv vs disadvantages of wave powered energy in fish hoek

Answer 17

adv
Ideal for an island country.
More likely to be small local operations, rather than done on a national scale.
disadv.
costly.
May be opposed by local or environmental groups.

Question 18

adv vs disadvantages of solar powered energy in fish hoek

Answer 18

adv.
Potentially infinite energy supply.
Single areas can have own electricity supply.
disadv.
 costly.

Question 19

where does wave energy come from?

Answer 19

The movement of seawater in and out of a cavity on the shore compresses trapped air, driving a turbine.

Question 20

where does wind energy come from?

Answer 20

Wind turbines (modern windmills) turn wind energy into electricity.

Question 21

where does solar energy come from?

Answer 21

Energy from sunlight is captured in solar panels and converted into electricity.

Question 22

what is Ohm’s law?

Answer 22

a law stating that electric current is proportional to voltage and inversely proportional to resistance.

Question 23

Resistors in Series

Answer 23

RT = R1 + R2 + R3.

Question 24

resistors in parallel

Answer 24

1/Rt = 1/R1 + 1/R2 + 1/R3