Energy

Question 1

How do you calculate energy usage?

Answer 1

Energy (KWH) = Power (KW) x Time (hrs)

Question 2

What does ‘standing charge’ mean?

Answer 2

Being charged for being connected to electricity

Question 3

? Watt = ? Joules/?

Answer 3

1 watt = 1 Joule/ second

Question 4

What is non-renewable energy?

Answer 4

Energy that cannot be replaced

Question 5

What are the 9 energy types?

Answer 5

Kinetic
Heat
Light
Gravitational potential 
Chemical
Sound
Elastic potential 
Electrical 
Nuclear

Question 6

What is the acronym for remembering the energy types?

Answer 6

Kids hate learning g c s e energy names

Question 7

What are Sanky diagrams?

Answer 7

Displays energy input and energy usage

Question 8

What do Sanky diagrams look like?

Answer 8

Oven mitts

Question 9

How do Snaky diagrams display the info

Answer 9

Input energy on the left, on energy usage on the right, and the other at the bottom

Question 10

What unit is electrical energy measured in?

Answer 10

Kilo-watt hours

KWH

Question 11

What is the equation for power?

Answer 11

Power(W) = Current(I) x Voltage(v)
I x V = P
Or
Energy(kWh) / time (hrs)

Question 12

What is A.C and D.C?

Answer 12

A.C is alternating current

D.C is direct current

Question 13

What does an ammeter do?

Answer 13

Measure current, Amps

Question 14

What does a voltmeter do?

Answer 14

Measure voltage, volts

Question 15

What is an electric current?

Answer 15

The rate of flow of charge

Question 16

What is voltage?

Answer 16

The amount of energy carried by each unit of charge

The electrical equivalent to pressure

Question 17

How can we generate energy (three things)

Answer 17

Moving a magnet near a coil

Magnet, coil, movement

Question 18

What does a coil and magnet induce?

Answer 18

It induces a voltage, which causes a current to flow

Question 19

What happens when you change the direction of the movement of the magnet?

Answer 19

The direction of the induced voltage will change, changing the direction of the current.

Question 20

How do you change the size of the induced voltage and current?

Answer 20

Change the strength of the magnet
Change the speed of movement
Change the number of coils

Question 21

How do you calculate the power of a battery in a circuit?

Answer 21

Multiply the voltmeter reading by the ammeter reading

P = I x V

Question 22

What is the voltage of mains electricity?

Answer 22

230 V

Question 23

What do step up transformers do?

Answer 23

Step the alternating voltage up at one end,Bring it back down to safe useable levels at other end

Question 24

What is the voltage across power lines?

Answer 24

440 KV

Question 25

What is the equation to calculate the output voltage from a transformer?

Answer 25

Primary voltage/ secondary voltage = no. Of turns on primary coil/ no. Of turns on secondary coil

Question 26

What goes before and after the lightbulb in a circuit?

Answer 26

Voltmeter

Question 27

What are some ways to reduce energy waste in a house?

Answer 27

Curtains
Loft insulation 
Draught excluders
Double glazing
Cavity walls

Question 28

What is the equation for payback time?

Answer 28

Payback time = cost/ savings per year

Question 29

Why do the lamps reach a constant temperature even though energy is still being supplied to them?

Answer 29

Energy is emitted at the same rate it is supplied

Question 30

Most of the wasted power is thermal.
The motor runs at a steady speed.
The motor begins to warm up.
Explain what happens to the temperature of the motor as the motor continues to run.

Answer 30

The motor reaches a constant temperature (equilibrium reached) the power lost equals power supplied

Question 31

The National Grid transmits electricity around the country.
Explain how using transformers makes the transmission of electrical energy
more efficient.

Answer 31

• transformers change voltage and/or current
• transformers use a.c.
• the current warms the transmission wires
• step-up transformers increase the voltage
• step-up transformers decrease the current
• energy is wasted
power depends on both current and voltage
• power = current × voltage (P = I × V)
• at high voltage, the same power needs less current
• correct mention of turns ratio related to voltage change
• a smaller current in a wire produces less heat
when you use a higher voltage, the current is lower. With lower
current, the amount of heat produced is less. If less heat is lost,
the efficiency is greater.
• correct use of (P = I × V) to show that current is less in the
transmission wires. Less heat is lost because the current is lower.
If less heat is lost, the efficiency is greater.
• current wastes heat in wires. Using a higher transmision voltage,
and therefore a lower current, saves more energy in the
transmission wire than is lost in the transformers