Heat Temperature and Modes of Heat Transfer II

Determine the mode of heat transfer:

Ironing clothes

• Conduction

• Convection

• Radiation

• Mass trasnport

Answer explanation

Ironing clothes primarily involves conduction, as the heat from the iron is directly transferred to the fabric through contact. This process effectively removes wrinkles by applying heat directly to the material.

Bran heats a kettle of water on the stove, what is the primary mode of transfer?

• Conduction

• Convection

• Radiation

• Conduction & Convection

Answer explanation

The primary mode of heat transfer in this scenario is conduction, as the kettle directly contacts the stove, allowing heat to transfer through the material. Convection occurs in the water, but conduction is the main process here.

Paulo toasts the bread on a toaster. Which of the following statements is TRUE?

• • Heat transfers through conduction from the hot metal heating elements to the bread slices in direct contact with them.

• Warm air circulates within the toaster, helping to evenly toast the bread by the process of convection.

• Heat is radiated from the heating elements, warming the surfaces of the bread.

• "The primary mode of heat transfer is conduction, as it directly transfers heat from the heating elements to the bread. Meanwhile, convection and radiation serve as secondary modes of heat transfer, contributing to the overall toasting process by circulating warm air and radiating heat, respectively

Answer explanation

The correct statement highlights that conduction is the primary mode of heat transfer, directly heating the bread from the toaster's elements, while convection and radiation assist in the overall toasting process.

When heating soup on the stove, what is the primary mode of heat transfer?

• Conduction

• Convection

• Radiation

• Conduction and Convection

Answer explanation

The primary mode of heat transfer when heating soup on the stove is convection. As the soup heats, warmer, less dense liquid rises while cooler, denser liquid sinks, creating a circulation pattern that distributes heat evenly.

Which of the following statement is TRUE when you take a hot shower?

• Conduction: When you touch the hot water pipe, heat is transferred from the pipe to your skin.

• The warm water vapor rises in the shower, warming the air around you and creating a steamy environment.

• You feel the warmth of the steam on your skin, which is heat energy transferred through radiation.

• The movement of water and steam helps distribute heat unevenly in the shower area

Answer explanation

The correct statements describe heat transfer methods: conduction occurs when touching the hot pipe, warm vapor rises to warm the air, and steam warmth is felt through radiation.

When stirring hot cocoa with a metal spoon, the movement of heat transfer occurring is primarily through:

• Conduction

• Convection

• Radiation

• Mass Transfer

Answer explanation

When stirring hot cocoa with a metal spoon, heat is transferred primarily through conduction. The metal spoon conducts heat from the hot cocoa to its cooler parts, allowing for efficient heat transfer.

Additionally, when you stir the cocoa, which mode of heat transfer helps distribute the heat evenly throughout the liquid?

• Conduction

• Convection

• Radiation

• Mass Transfer

Answer explanation

Convection is the mode of heat transfer that occurs in fluids, where warmer, less dense areas rise and cooler, denser areas sink. Stirring the cocoa promotes convection, helping to distribute heat evenly throughout the liquid.

What is the boiling point of water in Kelvin?

• 100^OK

• 32^OK

• 273^OK

• 373.2^OK

Answer explanation

The boiling point of water is 100°C, which converts to 373.2 K. The other options (32 K and 273 K) correspond to freezing point and absolute zero, respectively, making 373.2 K the correct answer.

A mother is cooking food using a pan on a stove. What mode of heat transfer is applied?

• Convection

• Conduction

• Radiation

• Advection

Answer explanation

The correct answer is conduction because the heat from the stove directly transfers to the pan through direct contact, cooking the food. Convection involves fluid movement, while radiation does not apply here.

What cause heat to flow or transfer?

• temperature difference

• difference in mass of objects in contact

• pressure difference

• difference in size of objects in contact

Answer explanation

Heat transfer occurs due to a temperature difference between objects. Heat flows from the hotter object to the cooler one until thermal equilibrium is reached, making 'temperature difference' the correct answer.