Heat Transfer 2024

Front

What is the definition of CONDUCTION?

Back

When heat transfers from objects that are touching.

Answer explanation

Conduction is defined as the transfer of heat through direct contact between objects. This occurs when molecules in a hot object collide with those in a cooler object, transferring energy. Thus, the correct answer is when heat transfers from objects that are touching.

Front

Transfer of thermal energy through a vacuum "empty space"

Back

radiation

Answer explanation

Transfer of thermal energy through a vacuum occurs via radiation, as it does not require a medium. Conduction and convection need matter to transfer heat, making radiation the correct choice for empty space.

Front

The baby chickens are kept warm from the heat lamps demonstrates this type of heat transfer.

Back

radiation

Answer explanation

The heat lamps warm the baby chickens through radiation, which is the transfer of heat in the form of infrared energy. Unlike conduction and convection, radiation does not require direct contact or a medium to transfer heat.

Front

Considering that convection is driven by differences in temperature, double-pane windows are most likely used to

Back

decrease the rate of heat flow to the outside air.

Answer explanation

Double-pane windows trap air between the panes, reducing heat transfer. This design decreases the rate of heat flow to the outside air, minimizing energy loss and maintaining indoor temperature.

Front

In the winter, Carole mostly uses the downstairs unit because the volume of warm air __________ and __________ warming the whole house through __________.

Back

expands, rises, convection

Answer explanation

In winter, warm air expands and rises due to convection, effectively warming the whole house. This process explains why Carole primarily uses the downstairs heating unit.

Front

What happens when ice cubes melt in a glass?

Back

Heat is transferred from the warmer water to the ice cubes.

Answer explanation

When ice cubes melt in a glass, heat is transferred from the warmer water to the ice cubes, causing them to melt. This process cools the water slightly as it loses heat.

Front

Over the next 15 minutes, which changes would most likely occur in the heat-flow experiment with two insulated Styrofoam cups of water connected by an aluminum bar?

Back

The temperature in cup A will decrease and the temperature in cup B will increase.

Answer explanation

In this heat-flow experiment, heat will transfer from the warmer water in cup A to the cooler water in cup B through the aluminum bar. Thus, the temperature in cup A will decrease while the temperature in cup B will increase.

Front

The diagram shows two insulated Styrofoam cups of water connected by an aluminum bar. The thermometers show the temperature of the water in cup A and cup B at the beginning of a heat-flow experiment. Which process is most responsible for the temperature changes that will take place?

Back

conduction of heat through the aluminum bar

Answer explanation

The temperature changes occur primarily due to the conduction of heat through the aluminum bar, which facilitates heat transfer between the two cups of water, leading to temperature changes.

Front

The diagram shows a Bunsen burner heating a beaker of water on a beaker stand. The arrows represent the transfer of heat energy in the water. Which process is primarily responsible for the transfer of heat indicated by the arrows in the beaker of water?

Back

convection

Answer explanation

The heat transfer in the beaker of water is primarily due to convection. As the water at the bottom heats up, it becomes less dense and rises, while cooler water descends, creating a circulation pattern that transfers heat throughout the water.

Front

The diagram shows two insulated Styrofoam cups of water connected by an aluminum bar. The thermometers show the temperature of the water in cup A and cup B at the beginning of a heat-flow experiment. If the temperature of the water in cup A continues to decrease as shown on the graph, what will the approximate temperature of the water in cup A be at the end of 25 minutes?

Back

78°C

Answer explanation

The graph indicates that the temperature in cup A decreases steadily. After 25 minutes, it approaches 78°C, which is the closest value to the expected final temperature, making 78°C the correct answer.