Energy Flow and Thermodynamics

Flashcards based on lecture notes about energy flow and thermodynamics.

What does the law of conservation of energy state?

Energy can neither be created nor destroyed, but can be converted from one form to another.

What type of energy conversion does an electrical room heater perform?

Electrical energy into heat energy.

What type of energy conversion does a thermocouple perform?

Heat energy into electric energy.

In archery, what energy conversion occurs when an arrow is released from a bow?

Potential energy of the pulled string converts to kinetic energy of the arrow.

What type of energy conversion does a microphone perform?

Sound energy into electric energy.

What type of energy conversion does a loudspeaker perform?

Electric energy into sound energy.

Describe a sequential conversion of energy.

Mechanical energy can be converted into electrical energy, which can be converted into heat and light energy, and then stored as chemical energy.

What are the two types of mechanical energy?

Kinetic and potential energy.

What is meant by 'linear flow' of energy?

The conversion of energy in the reverse sense is not always possible; the flow of energy is a linear flow.

According to the law of conservation of energy, how does the final total energy compare to the initial total energy in any energy conversion?

The final total energy is always equal to the initial total energy.

How efficient is energy transfer in real-world scenarios?

No energy transfer is 100% efficient.

How is the efficiency of energy transfer defined?

The ratio of the required form of output energy obtained to the input energy supplied.

What is thermodynamics?

The branch of science concerned with the conversion of heat energy into other forms of energy and vice versa.

What does the first law of thermodynamics state?

Energy is conserved in nature.

What limitation does the second law of thermodynamics impose on heat engines?

A heat engine can never be 100% efficient./ The heat energy supplied to a heat engine, can never be converted completely into mechanical work.

According to the Second Law of Thermodynamics, how does heat flow between objects of different temperatures?

Heat flows from a body at higher temperature to one at a lower temperature.

In a food chain, which organisms can produce their own food?

Plants.

What are plants referred to as in a food chain?

Producers.

What are organisms that consume plants known as?

Herbivores/primary consumers.

What are organisms that consume herbivores known as?

Carnivores/secondary consumers.

Why is the flow of energy in a food chain not a cyclic process?

The process is clearly not a cyclic process.

Name cycles in nature.

The Water Cycle, the Nitrogen Cycle, the Carbon Cycle, and the Oxygen Cycle.

When is a mechanism of energy transfer efficient?

When the required output energy obtained is a high percentage of the input energy.