Conservation Of Energy

Question 1

Where is energy stored?

Answer 1

Pretty much anywhere

Question 2

What energy is stored in food, fuel and batteries.

Answer 2

Chemical energy

Question 3

What energy is stored in moving objects?

Answer 3

Kinetic energy

Question 4

What energy is stored in hot objects?

Answer 4

Thermal energy

Question 5

What energy is conserved in stretched, squashed or twisted materials?

Answer 5

Strain energy or elastic potential energy

Question 6

What energy is conserved in high positions?

Answer 6

Gravitational potential energy

Question 7

What an energy is conserved inside atoms?

Answer 7

Atomic energy or nuclear energy

Question 8

Give 2 examples of energy being moved between different stores?

Answer 8

When an electric kettle is used to heat up water, energy transferred to the kettle by electricity ends up as a store of thermal in the hot water

Question 9

Name 3 ways energy is transferred

Answer 9

Heating, electrically, by radiation

Question 10

What can energy not be?

Answer 10

Created or destroyed

Question 11

What can energy only be and what is this called?

Answer 11

It can only be transferred from one store to another, this is called the law of conservation of energy. The total energy transferred by the system is the same as the energy put into the system

Question 12

What are the units for measuring energy?

Answer 12

Joules (J)

Question 13

What happens to wasted energy in energy transfers?

Answer 13

Goes into the surrounding

Question 14

Is energy always transferred into forms that are useful?

Answer 14

No, even though energy is always conserved, think of the kettle-the energy stored in the hot water is useful but the energy stored in the kettle itself and the surroundings is not

Question 15

What shows the amount of energy transferred and what do the arrows represent?

Answer 15

A sankey diagram and the arrows represent the amount of energy in joules

Question 16

Explain a way in which energy is transferred wastefully by mechanical processes

Answer 16

When a light bulb is switched on most of the energy supplied to it by electricity is transferred to the surroundings by heating. This energy is dissipated (it spreads out) and cannot be used for other useful energy transfers, it’s wasted

Question 17

How can you reduce unwanted energy energy transfers in mechanical processes?

Answer 17

If it’s friction you can reduce it by lubrication, or you can reduce it by finding ways to make sure all the energy is going to good use

Question 18

What is efficiency?

Answer 18

It is a way if describing how good a machine is at transferring energy into useful forms

Question 19

How can efficiency be increased?

Answer 19

Be reducing the amount of wasted energy

Question 20

What’s the formula for calculating energy efficiency?

Answer 20

Efficiency = useful energy transferred by the device ➗ total energy supplied to the device

Question 21

When energy is transfer by heating What is conduction?

Answer 21

Vibrations that are passed on between particles in a solid

Question 22

What are metals good?

Answer 22

Thermal conductors

Question 23

What are materials such as wood bad?

Answer 23

Thermal conductors but they are good thermal insulators

Question 24

In energy transferred by heating what is convection?i

Answer 24

It’s part of a fluid that is warmer than the rest

Question 25

How is energy stored?

Answer 25

In different ways

Question 26

What is the only way in high energy can be transferred through a vacuum?

Answer 26

Radiation. Infrared radiation can also pass through gases and some solid materials. Infrared radiation is absorbed and emitted easily by dark dull surfaces, and is absorbed and emitted poorly by light and shiny surfaces

Question 27

How do you reduce energy transfers?

Answer 27

Increasing thickness of a material, decreasing thermal conductivity and decreasing temperature difference

Question 28

Why is air a good thermal insulator?

Answer 28

Air is good thermal insulators because it has a very low thermal conductivity. When air is trapped it cannot from convection currents and so does not transfer much energy

Question 29

What is thermal conductivity?

Answer 29

Energy is transferred through materials by heating

Question 30

What happens when the thickness of a wall is thicker?

Answer 30

Less energy escapes

Question 31

How different factors affect the gravitational potential energy stored in an object?

Answer 31

Every time something is moved upwards, it stores more gravitational potential energy. Any object that is above the surface of the earth contains a store of gravitational potential energy The amount depends on the mass of an object, the strength of gravity and how far the object is moved upwards

Question 32

What's the equation for gravitational potential energy?

Answer 32

Change in gravitational potential energy (j) = mass(kg) X gravitational field strength (n/kg) X change in vertical height (m)

Question 33

What factors affect the kinetic energy stored in an object?

Answer 33

mass, and it's speed affect the amount of Kinect energy

Question 34

What's the equation for Kinect energy?

Answer 34

Kinetic energy (j) = 1/2 X mass (kg) X (speed) squared, (m/s) squared

Question 35

How can you reduce energy transfers by heating?

Answer 35

Insulation slows down the rate at which energy is transferred out of the house by heating When materials have a low thermal conductivity energy is not transferred very easily by heating Materials containing air are good insulators because air has a very low thermal conductivity. When air is trapped it cannot form convection currents and so does not transfer much energy