Thermodynamics and Heat engines

Answer in number only

If the change in internal energy is positive, does the temperature of the system increase or decrease?

• Increase
• Decrease

If an engine has a hot reservoir with a temperature of 980 K and cold reservoir of 673 K. Give the maximum efficiency of the engine rounded to the nearest tenth.

An engine takes in 11400 Joules of energy while exhausting 8200 Joules of energy. How much work was performed by the engine in joules

If a heat engine exhausts 360 J of energy after performing 180 J of work. How much energy was provided from the hot reservoir?

A gas in a closed container is heated with 10J of energy, causing the lid of the container to rise 2m with 3N of force. What is the total change in energy of the system?

Which of the following represents the first law of thermodynamics?

• The specific heat of an object explains how easily it changes temperatures
• While melting, an ice cube remains at the same temperature
• Two systems in equilibrium with a third system are in equilibrium with each other
• After falling down the hill, a ball's kinetic energy plus heat energy equals the initial potential energy
• If a refrigerator is unplugged, eventually everything inside of it will return to room temperature

A glass of cold water is placed in a sealed room. After an infinite amount of time, what will happen?

• Both the water and the air will remain the same temperature, unless an outside force is applied
• The water will warm and the air in the room will cool, until they are the same temperature
• There is insufficient information to solve
• The water will warm to the temperature of the air
• The air will cool to the temperature of the water

When boiling water in a pot, what type of heat transfer primarily occurs?

• Conduction

• Induction

• Convection

• Radiation

When sunlight warms your face, what type of heat transfer are you experiencing?

• Convection

• Conduction

• Radiation

• Induction