Y10 TERM 2 - Energy Stores and Transfers

Question 1

EFFICIENCY EQUATION

Answer 1

efficiency = useful energy output / total energy input x100

Question 2

PRINCIPLE OF CONSERVATION

Answer 2

The Law of Conservation of Energy states that energy cannot be created or destroyed in any process. Therefore it can only be transferred and can also be conserved.

Question 3

CONDUCTION

Answer 3

( Conductors: metal, tap water )

• when one ATOM gains THERMAL ENERY
• it starts to VIBRATE
• it will COLLIDE with neighbouring atoms
• TRANSFER thermal energy

Question 4

CONVECTION

Answer 4

Occurs only in liquids + gases ( fluids )

Question 5

INFRARED RADIATION

Answer 5

Infrared radiation is the transfer of heat as waves. This means it does not need particles to travel and can travel in a vacuum, like from the sun to the earth.

Question 6

WHEN ABSORBING HEAT

Answer 6

• BLACK IS GOOD at absorbing heat

- WHITE IS BAD at absorbing ( and reflects )

Question 7

WHEN EMITTING HEAT

Answer 7

• BLACK IS A GOOD emitter

- WHITE IS A BAD emitter

Question 8

WAYS OF REDUCING UNWANTED ENERGY TRANSFER, SUCH AS INSULATION

Answer 8

At home:

• double glazing windows
• using draught excluders
• blocking unused chimneys
• foam in wall cavity
• put carpets on the floor
• layer of roof insulation

Question 9

WORK DONE EQUATION

Answer 9

work done = force x distance moved

W = F x d

Question 10

WORK DONE AND ENERGY TRANSFERRED…

Answer 10

ARE ALWAYS THE SAME

Question 11

GRAVITATIONAL POTENTIAL ENERGY EQUATION

Answer 11

gravitational potential energy =

mass x gravitational field strength x height

Question 12

KINETIC ENERGY EQUATION

Answer 12

kinetic energy = 1/2 x mass x speed2

KE = 1/2 x m x v2

Question 13

POWER

Answer 13

• Power is the rate of work
• Power is also the rate of energy transfer
• So power is how quickly these processes are done

Question 14

POWER EQUATION

Answer 14

power = work done / time taken

P = w / t