Physics Energy Conservation and Efficiency

These flashcards cover fundamental concepts regarding the conservation of energy, efficiency in systems, and practical applications related to thermal dynamics and 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 with no external forces?

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

What energy changes occur in a filament light-bulb?

Electrical energy is transferred into light and heat energy.

What is light in the context of energy from a light-bulb?

Light is a useful energy form, while heat is considered waste energy.

What is the first equation for calculating efficiency?

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

What is the second equation for calculating efficiency?

Efficiency = Useful Power Output / Total Power Input.

How can the efficiency of a system be increased?

By reducing waste output and recycling waste output.

What is an example of reducing waste output?

Using lubrication or thermal insulation.

What consequence does high thermal conductivity have on energy transfer?

The rate of energy transfer through the material is higher.

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

Lower thermal conductivity.

What is the effect of lower thermal conductivity in double-glazed windows?

Less energy transfers through them.

What factors affect the rate of cooling of a building?

The thickness and thermal conductivity of the walls.

What are three methods to reduce heat loss in a building?

Double glazing, loft and wall insulation, thicker walls.

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

By lubricating moving parts to reduce friction.

What is the benefit of reducing friction in machines?

It decreases energy loss due to heating.

How can the efficiency of a radiator be improved?

By installing metal foil sheets behind it to reflect heat back into the room.

What is the effect of installing metal foil sheets behind a radiator?

It prevents heat from being absorbed into the walls.

How can boiling water in a pan be more efficient?

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

What happens to heat loss when a lid is placed on a pan?

It reduces heat loss from the top of the pan.

What is the general principle of increasing system efficiency?

Minimizing waste and optimizing energy transfer.

In energy conservation, what forms can energy be transferred into?

Different forms such as kinetic, potential, thermal, etc.

What is the relationship between thermal conductivity and heat loss?

Higher thermal conductivity typically results in greater heat loss.

Which type of windows are more energy efficient in terms of thermal conductivity?

Double-glazed windows.

List a method of increasing efficiency related to waste recycling.

Recycling thermal waste energy as input energy.

What role does insulation play in energy conservation?

It helps to reduce undesired energy transfer such as heat loss.

Why is thicker wall construction beneficial for energy conservation?

It reduces heat loss and enhances thermal efficiency.

What impact does adding insulation material have on a building?

Increases the thermal resistance and keeps heat inside.

Describe an energy transfer process in electrical appliances.

Electrical energy is transformed into useful forms like light or mechanical motion.

What can be a waste product of energy transfer in appliances?

Heat energy that is not utilized.

In terms of efficiency, what should be minimized to improve performance?

The unproductive energy outputs.

What is a common household method for improving thermal efficiency during cooking?

Using lids on pans.