unit 7 class 8

Question 1

What is a fuse?

Accepted Answer

electrical safety device that can stop current from flowing if it overloads

Question 2

What is voltage?

Accepted Answer

The push on electrons

Question 3

What is resistance?

Accepted Answer

Difficulty to pass an electric current through a conductor.

Question 4

What is is circuit breaker

Accepted Answer

Reusable safety switch that breaks the circuit

Question 5

Where Ac used?

Accepted Answer

tv

Question 6

What is the voltage across a 75Ω resistor with a current of 10A?

Accepted Answer

750V

Question 7

MCB stands for?

Accepted Answer

Miniature Circuit Breaker

Question 8

What causes a circuit breaker to break the circuit?

Accepted Answer

The current becomes too high

Question 9

What is a sankey diagram used for?

Accepted Answer

efficiency of a product, summaries all the energy transfers taking place in a process

Question 10

Is a light bulb represented by this Sankey diagram an efficient light bulb?

Accepted Answer

Yes

Question 11

A thermal power station uses

Accepted Answer

fossil fuels

Question 12

Who discovered electricity?

Accepted Answer

ben frankilin

Question 13

In a Sankey Diagram which arrow represents wasted energy?

Accepted Answer

Orange

Question 14

What will the reading be after using 222 more kWh of electricity?

Accepted Answer

7798

Question 15

What voltage enters a domestic property?

Accepted Answer

230v

Question 16

How do you calculate kWh

Accepted Answer

(Power in kW) x (Time in hours)

Question 17

Calculate the power.

Accepted Answer

2W

Question 18

Using kWh is the same as saying the amount of energy that has been used.

Accepted Answer

True

Question 19

In a thermal power station, what is used to drive the turbine?

Accepted Answer

Steam

Question 20

A hydro-electric power station makes use of the ____________ of water to generate electricity.

Accepted Answer

kinetic energy

Question 21

Which of the following is NOT a characteristic of a sankey diagram?

Accepted Answer

the arrow pointing downwards is the total energy

Question 22

A pathway for the flow of electricity:

Accepted Answer

circuit

Question 23

What is the difference between AC and DC?

Accepted Answer

AC is an alternating current while DC is a direct current

Question 24

In a Sankey Diagram which arrow represents useful energy?

Accepted Answer

Yellow

Question 25

What type of power station is this?

Accepted Answer

Hydroelectric

Question 26

In a power station, the correct sequence of events would be ....

Accepted Answer

Burn fuel > Boil water > Steam > Turbine > Generator

Question 27

fuses are always connected in live wires

Accepted Answer

True

Question 28

A circuit breaker protects

Accepted Answer

the device(load)

Question 29

What does the resistor do?

Accepted Answer

Slows the flow of electrons

Question 30

What device could this be a Sankey diagram for?

Accepted Answer

A high efficiency light bulb.

Question 31

A kilowatthour is energy!

Accepted Answer

True

Question 32

This resists the flow of electricity

Accepted Answer

insulator

Question 33

What is resistance measured in?

Accepted Answer

Ohms

Question 34

What energy conversion takes place in a hydro-electric power station?

Accepted Answer

Kinetic energy to electrical energy.

Question 35

What object would this sankey diagram refer to?

Accepted Answer

Car

Question 36

The symbol for resistance

Accepted Answer

What is OhmsΩ

Question 37

Energy transfers in a power station go from

Accepted Answer

chemical → heat → kinetic → electrical

Question 38

What is electricity?

Accepted Answer

A form of energy

Question 39

What is the unit for voltage?

Accepted Answer

volt, V

Question 40

The way we identify a resistors resistance

Accepted Answer

What is color coding

unit 7 class 8

Questions 40

unit 7 class 8

Questions 40