Identify a correct pairing of heat transfer mode and its example.

• A. Conduction: heat transfer via air currents; Convection: heat transfer through a metal rod; Radiation: heating by touch.
• B. Conduction: heat transfer through a metal rod along its length; Convection: airflows remove heat from a hot surface; Radiation: sun warming the earth.
• C. Conduction: heat transfer through vacuum.
• D. Convection: heat transfer by radiation.

Answer: (B)

Understanding heat transfer modes—conduction, convection, and radiation—helps you match each mode to real-world examples. Conduction occurs through a material because particles transfer kinetic energy to their neighbors, so heat moves along a metal rod from hot to cold. Convection involves the bulk movement of a fluid (air or liquid), carrying heat with the moving fluid, such as hot air rising and carrying away heat. Radiation is energy transfer by electromagnetic waves and can occur through empty space, like the sun warming the Earth.

That’s why pairing conduction with heat transfer through a metal rod along its length, convection with airflows removing heat from a hot surface, and radiation with the sun warming the Earth is correct. The other options mix up the modes or rely on impossible conditions—heating by touch is conduction, not radiation; conduction cannot occur through a vacuum because there are no particles to transfer energy; and convection is not heat transfer by radiation.