1.2 - Energy Conservation and Efficiency

Flashcards covering key concepts of energy conservation, efficiency, and methods to improve energy transfer.

What is the law of energy conservation?

Energy cannot be created or destroyed; it can only be transferred into different forms.

What happens to the total energy of a ball that is kicked assuming no external forces act upon it?

The total energy of the system remains constant due to the conservation of energy.

What type of energy is transferred in a filament light-bulb?

Electrical energy is transferred into light and heat energy.

What is the formula for efficiency based on energy transfer?

Efficiency = Useful Output Energy Transfer / Total Input Energy Transfer.

How can the efficiency of a system be increased?

By reducing waste output and recycling waste output.

What is the consequence of a material with high thermal conductivity?

The rate of energy transfer through the material is higher than for a material with lower thermal conductivity.

Do double-glazed windows have a higher or lower thermal conductivity than single-glazed windows?

Lower, meaning less energy transfers through them.

What key factors affect the rate of cooling of a building?

The thickness of the walls and the thermal conductivity of the walls.

Name three methods of reducing heat loss in a building.

1. Double glazing; 2. Loft and wall insulation; 3. Thicker walls.

How can the efficiency of a mechanical machine with moving parts be improved?

Lubricate any moving parts to reduce friction and therefore energy loss due to heating.

How can the efficiency of a radiator be improved?

Install metal foil sheets behind the radiator to reflect heat back into the room.

How can the efficiency of boiling water in a pan be improved?

By placing a lid on the pan to reduce heat loss from the top.