# Deck 1 = Physics start of year- 10/10/13 Flashcards

## revision for half term tast

1
Q

What is energy measured in?

A

-Joules.

2
Q

Name types of energy?

A

-Chemical potential, kinetic, gravitational potential, potential, elastic potential, nuclear potential, thermal energy, electrical, radiation.

3
Q

What is energy measured in?

A

-Joules.

4
Q

Law of energy conservation?

A

-Energy can not be destroyed, During each transformation, the total amount of energy stays the same.

5
Q

What happens to GPE as you climb?

A

-It increase.

6
Q

Gravitational field strength on earth?

A

-10 newton per kilogram.

7
Q

What is the efficiency equation?

A

-Efficiency = useful power output (w) over power input (w).

8
Q

Work done =

A

-Energy transformed measured in J.

9
Q

Unit for energy efficiency?

A

-No unit, or percentage.

10
Q

What is kinetic energy measured in?

A

-J

11
Q

What is thermal energy measured in?

A

-J

12
Q

What is chemical potential measured in?

A

-J

13
Q

What is power measured in?

A

-W

14
Q

Define work?

A

-Work is done whenever a force make something move. The greater the force and the greater the distance moved, the more work is done.

15
Q

One joule=

A

-One newton meter.

16
Q

If an engine does 2000J of useful work in 2 seconds, what is its power output?

A

-1000J

17
Q

Engine does 25J of useful work for every 100J of energy supplied, what is its efficiency?

A

-0.25 or 25%

18
Q

Rearrange GPE=mgh to find H?

A

-GPE over mg = H

19
Q

Equation for Kinetic energy?

A

-KE=0.5mv2 (squared).

20
Q

The higher the temp…

A

-The faster the atoms moving.

21
Q

Absolute zero =

A

-273oC 0K this can never be reached because you need something colder to take away the thermal energy.

22
Q

When we say to things are at the same temp, this means…

A

-They do not have a thermal energy transfer.

23
Q

Standard atmospheric pressure.

A

-101325 Pa.

24
Q

When you put a hot and a cold thing together…

A

-The hot thing loses its kinetic energy and the cold thing gains Kinetic energy.

25
Q

Define Conduction?

A

-This is when thermal energy or randomized kinetic energy is transferred from one place to another due to collisions between particles. This happens more quickly in metals.

26
Q

Particles in hot objects…

A

-Vibrate with a large amplitude. large then that of liquids and gasses.

27
Q

What is convection?

A

-Liquids and gases are poor thermal conductors however they are free to circulate and they are also aloud to carry thermal energy from one place to another quickly.

28
Q

Define convection current?

A

-Liquids or gasses become less dense when they are heated making them rise. they then cool and sink. It happens in a circle, this i called a convection current.

29
Q

How can you reduce convection?

A

-By holding or trapping air in place.

30
Q

How does this happen with a fridge?

A

-Cold air sinks because it is more dense and the hot air rises. then the hot are is sucked out the fridge.

31
Q

How does conduction work?

A

-Particles vibrating with big amplitude transfer their kinetic energy to there neighbor through collisions.

32
Q

How does convection work?

A

-Heated fluids expand, becoming less dense and rising. cooler fluids do the reverse, this sets up a convection current.

33
Q

A

-All objects emit inferred or thermal radiation. Hot objects emit more. When this energy is absorbed energy in transformed.

34
Q

How do we minimize conduction?

A

-Use insulator.

35
Q

A

-Paint an object white or give it a silver reflective surface.

36
Q

How do we maximize conduction?

A

-Use a good conductor such as copper.

37
Q

How to maximize convection?

A

-Allow the fluid to move freely.

38
Q

A

-Paint an object black, this maximizes emissions and absorption.

39
Q

What is time measured in?

A

-Seconds (s)

40
Q

What is energy transferred measured in?

A

-J

41
Q

What is work done measured in?

A

-J

42
Q

Efficency equation?

A

-Useful power over total power input.

43
Q

Equation for power?

A

-Energy transferred (j) over time (s).

44
Q

Power Work done equation, Power =

A

-Work done over time. Wd/t.

45
Q

Power Energy equation, Power=

A

-Energy (j) over time (s).

46
Q

How to make a house more energy efficient?

A
• Loft insulation.
• Double glazing.
• For doors and windows use draft exclude.
47
Q

What is the process called when a material can only conduct in a liquid form?

A

-Electrolysis.