Using Thermal Energy, Thermodynamics

Multiple Choice

What is the significance of thermal energy in everyday life?

• It helps in cooking food only

• It is used in heating systems, engines, and refrigerators

• It is only important for scientific experiments

• It is not useful in daily activities

Open Ended

Explain how thermal energy is transferred from a stove to the surrounding air in a heating system.

Multiple Choice

Which type of heating system uses ducts to distribute warm air throughout a building?

• Radiator system

• Electric heating system

• Forced-air system

• Solar heating system

Multiple Select

Select all the correct statements about passive solar heating systems.

• Materials inside a building absorb radiant energy from the Sun during the day.

• Thermal energy absorbed by materials helps keep the room warm at night.

• Solar collectors are used to absorb radiant energy from the Sun.

• A pump circulates hot water to radiators in rooms of the house.

Fill in the Blanks

In active solar heating systems, the black

plate absorbs radiant energy from the Sun.

Multiple Choice

Which statement best describes how thermal energy can be increased in a system according to the first law of thermodynamics?

• By adding heat or doing work on the system

• By removing heat from the system

• By isolating the system from its surroundings

• By converting all energy to mechanical energy

Multiple Select

Which of the following statements are true about isolated systems?

• No energy transfers occur across the boundary

• No work is done across the boundary

• Total energy remains constant

• Thermal energy can be converted to another form

Open Ended

Explain the difference between an isolated and a non-isolated system in terms of energy and work transfers.

Fill in the Blanks

According to the second law of thermodynamics, energy spontaneously spreads from regions of

energy to regions of lower energy.

Fill in the Blanks

A device that converts thermal energy into mechanical energy is called a

engine.

Open Ended

Explain how thermal energy is converted to mechanical energy in a car engine, and why only a portion of the energy is used for mechanical work.

Multiple Choice

What is the main function of the crankshaft in an internal combustion engine?

• To burn fuel

• To move the piston up and down

• To convert the piston's up-and-down motion into rotational motion

• To cool the engine

Fill in the Blanks

A refrigerator transfers thermal energy

the refrigerator to the warmer room.

Multiple Choice

What happens to the coolant gas after it absorbs thermal energy from inside the refrigerator?

• It is compressed and becomes warmer than the room

• It evaporates and cools the refrigerator

• It condenses and releases thermal energy into the room

• It is pumped out of the refrigerator

Open Ended

Describe the role of coolant in the functioning of a refrigerator and how its state changes during the refrigeration cycle.

Multiple Select

Which of the following are steps in the refrigeration cycle?

• Coolant absorbs thermal energy inside the refrigerator

• Coolant is compressed and becomes warmer than the room

• Coolant evaporates at a high temperature

• Coolant is pumped through condenser coils

Multiple Choice

Which statement best describes how an air conditioner operates?

• It cools warm air and returns it to the room, transferring thermal energy outdoors.

• It heats the air and returns it to the room, transferring thermal energy indoors.

• It absorbs cold air from outside and releases it inside.

• It only circulates air without changing its temperature.

Open Ended

Compare the operation of a heat pump in warm weather and cold weather. How does its function change?

Fill in the Blanks

Your body uses

to keep its internal temperature constant by carrying away thermal energy as sweat evaporates.