P2: Energy Transfers

Question 1

What is the relationship between thermal conductivity and the amount of energy transferred?

Answer 1

The higher the thermal conductivity, the higher the rate of energy transfer by conduction

Question 2

What is the equation for specific heat capacity?

Answer 2

Energy transferred / mass x temperature change

Question 3

What is specific heat capacity?

Answer 3

The amount of energy required to raise the temperature of one kilogram of a substance by one degree

Question 4

What is a perfect black body?

Answer 4

An object that absorbs all of the radiation incident on it

Question 5

What is a body at constant temperature doing?

Answer 5

Absorbing temperature at the same rate it is emitting radiation

Question 6

When does the temperature of a body increase?

Answer 6

When the body absorbs radiation faster than it emits it

Question 7

What does the temperature of the Earth depend on?

Answer 7

The rates of absorption and emission of radiation and reflection of radiation into space

Question 8

How is heat transferred in fluids?

Answer 8

Convection

Question 9

How is heat transferred in empty space?

Answer 9

Radiation

Question 10

What is conduction?

Answer 10

The process by which vibrating particles transfer energy to neighbouring particles

Question 11

What is thermal conductivity?

Answer 11

How well an object transfers energy by conduction

Question 12

What are the 4 steps of conduction?

Answer 12

When an object is heated, the thermal energy is transferred to the kinetic energy of the particles. This causes them to vibrate faster so they collide with neighbouring particles more. These neighbouring particles also vibrate, and this process repeats so energy is passed along.

Question 13

What are the 4 steps of convection?

Answer 13

When a fluid is heated, the particles gain kinetic energy and this causes the fluid to become less dense, so will rise above any cooler fluid. As the fluid cools, it will become more dense and sink to the bottom again. If it takes place in a limited space, it can create a convection current

Question 14

What are 2 ways to reduce unwanted energy transfers?

Answer 14

Lubrication and thermal insulation

Question 15

How does making vehicles streamlined help reduce wasted energy?

Answer 15

Reduces the friction from air resistance, allowing them to use less fuel and makes them more efficient

Question 16

What is internal energy?

Answer 16

The total energy stored by particles making up a substance or system

Question 17

What are the 2 parts that make up internal energy?

Answer 17

Potential energy stores and kinetic energy stores