Energy (1)

Question 1

Name the energy store

Answer 1

• thermal energy
• kinetic energy
• gravitational potential energy
• elastic potential energy
• chemical energy
• magnetic energy
• electrostatic energy
• nuclear energy

Question 2

What is a closed system

Answer 2

• systems where neither matter nor energy can enter or leave

Question 3

what is work done

Answer 3

• energy transferred

- work done can be done when a current flows or by a force moving an object

Question 4

what does kinetic energy depend on

Answer 4

• mass and speed

Question 5

What does GPA depend on

Answer 5

• the objects mass, its height and the strength

Question 6

What is specific heat capacity

Answer 6

• the amount of energy needed to heat 1kg of substance by 1 degrees

Question 7

What are the instructions for the investigation of specific heat capacity

Answer 7

1) Place a small beaker into a larger beaker.
2) Fill the small beaker with hot water from a kettle.
3) Put a piece of cardboard over the beakers as a lid. The lid should have a hole suitable for a thermometer.
4) Place a thermometer into the smaller beaker through the hole.
5) Record the temperature of the water in the small beaker and start the stopwatch.
Record the temperature of the water every 2 minutes for 20 minutes.
6) Repeat steps 1-6, each time packing the space between the large beaker and small beaker with the chosen insulating material.
7) Plot a graph of temperature (y-axis) against time (x-axis).

Question 8

What is the conservation of energy principle

Answer 8

• Energy can be transferred usefully, stored or dissipated but can never be created or destroyed

Question 9

What is dissipated energy

Answer 9

• wasted energy from an energy transfer (energy is always dissipated in transfers, no transfer is 100% efficient)

Question 10

What is power

Answer 10

• the rate of energy transfer, or the rate of doing work

Question 11

what is conduction

Answer 11

• the process where vibrating particles transfer energy to neighbouring particles
• this mainly occurs in solids

Question 12

what is convection

Answer 12

• where energetic particles move away from hotter to cooler regions
• only occurs in liquids and gasses
• an example is a radiator

Question 13

How does lubrication reduce frictional forces

Answer 13

• when something moves, there’s usually always at least one frictional force acting against him
• lubricants can reduce the friction therefore reducing unwanted energy transfers

Question 14

how can you reduce heat loss in a house

Answer 14

• thicker walls
• cavity walls, made up of an inner and outer wall with an air gap in the middle, air gap reduces energy transfer through the wall
• loft insulation reduces convection currents created in the loft
• double glazed windows having an air gap between the sheets of glass to prevent energy transfer by conduction
• draught excluders around doors and windows reduce energy transfers by convection

Question 15

how do you investigate the effectiveness of materials as thermal insulators

Answer 15

1) Wrap a sheet of newspaper around a 100 ml beaker.
2) F ill the beaker with hot water from a kettle.
3) Put a piece of cardboard over the beaker as a lid. The lid should have a hole suitable for a thermometer.
4) Place a thermometer into the beaker through the hole.
5) Record the temperature of the water in the beaker and start the stopwatch.
6) Record the temperature of the water every 2 minutes for 20 minutes.
7) Repeat steps 1-6, each time adding another layer of newspaper around the beaker until there are 10 layers of newspaper wrapped around the beaker.
8) Plot graphs of temperature against time

Question 16

what is efficiency

Answer 16

• How good a device is at transferring energy input to useful energy output is called efficiency.