Energy Transfer

Question 1

Ways to transfer

Answer 1

1. Mechanically
2. Electrically
3. Heating
4. Light/Sound

Question 2

Energy transfer equation

Answer 2

Energy transferred (joules)= force (newtons) x distance (metres)

Question 3

Energy transfer by heating

Answer 3

• when there’s a temp difference between two objects, energy is transferred from the hotter one to the cooler one
• this carries on until the objects reach thermal equilibrium- same temperature

Question 4

Coduction

Answer 4

• when an object is heated, the particles start vibrating more and they gain kinetic energy
• conduction occurs when vibrating particles pass their extra energy to neighbouring particles
• this happens when they bump into each other
• hot object loses energy and cool object gains energy

Question 5

Radiation

Answer 5

• all objects radiate invisible waves that carry energy to the surroundings
• the hotter an object, the more energy it radiates
• radiation is not transferred by particles
• hotter object radiates more energy than cooler object
• cooler object absorbs some of the radiation from the hot object and it absorbs more than it radiates
• hotter object radiates more than it absorbs

Question 6

Equation for electricity transferred

Answer 6

Energy transferred (kWh) = power (kW) x time (h)

Question 7

Equation for cost of electricity

Answer 7

Cost= energy transferred x price per kWh