Physics 1- (heat And Energy)) Flashcards

1
Q

Unit of heat energy

A

Joule

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2
Q

Temperature is the measure of what

A

Average kinetic energy

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3
Q

The hotter something is?

A

The higher the average Ke

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4
Q

If there’s a difference in temperature between two places

A

Energy can flow between them

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5
Q

What generally happens to substances when heated

A

They expand

Increase in volume

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6
Q

Why are metals good conductors

A

Their electrons are free to move inside the metal

Allowing them to move KE/Heat

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7
Q

Why are non metals not good at conducting heat

A

Don’t have free electrons

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8
Q

Liquids conduct heat slower than what

A

Solids

As they have no free electrons

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9
Q

Why are gases very good thermal insulators

A

No free electrons

Particles are so far apart they don’t affect eachother

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10
Q

4 ways rate of conduction is affected by

A

Material

State of material

Surface area (larger=more collisions)

Temperature difference (bigger difference = higher rate of conduction)

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11
Q

The hotter an object is….

A

The more heat radiation it produces

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12
Q

For an object to stay at the same temperature

A

The power of heat absorbed must be equal to power of heat emitted

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13
Q

Dark matt surfaces absorb what

They also emit what

A

Heat radiation well

They emit more heat radiation

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14
Q

Bright glossy surfaces/silver do what?

A

Reflect all heat radiation on them

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15
Q

When does evaporation occur 2

A

Particles are travelling in the right direction

Travelling fast enough to overcome attractive forces of the other particles

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16
Q

Rate of evaporation will be faster if (3)

A

Temperature is higher (average KE higher)

Surface area is larger (more particles at surface edge)

Airflow over liquid is greater (lower concentration of evaporating substance in air = higher rate of evaporation. Air above the liquid is constantly being replaced keeping concentration of substance low)

17
Q

Rate of condensation is affected by what (3)

A

Gas temperature is low (causes particles to be slow and cause clumping )

Airflow is less (concentration of substance is higher =rate of condensation higher)

Temperature of the surface of the gas is lower

18
Q

Increasing surface area and volume does what to heat transfer

A

Increases transfer of heat (hence radiators)

Larger volumes will lose heat faster

19
Q

Good conductors do what to heat transfer

A

Transfer heat away quicker than insulators (plastic)

20
Q

Purpose of having large ears

A

Lose heat more quickly by radiation

Animals in desert

21
Q

Density equation

A

Mass / volume

22
Q

If the object has a lower density than the fluid

A

It will float

23
Q

How to find the density of a irregular shaped object

A

Mass =scales

Volume= beaker of water. The amount the water rose by is volume

24
Q

What are the stored forms of energy (3)

A

Chemical
Elastic potential
Gravitational potential

25
Q

9 types of energy

A
Electrical 
Light
Sound
Kinetic
Nuclear 
Thermal 
Gravitational
Elastic 
Chemical
26
Q

Efficiency =

A

energy out / energy in

27
Q

Why are electric heaters so efficient

A

There’s no “waste” energy as all waste is heat which is intended use