Q1: Fourier's law applies to the heat transfer by

ANS:C - conduction

Fourier's law applies specifically to heat transfer by: conduction. Explanation:

• Conduction: Fourier's law states that the rate of heat transfer through a material is directly proportional to the temperature gradient and the cross-sectional area, and inversely proportional to the distance along which the heat is transferred. This law applies to heat transfer within a solid or between two solids in contact.

• Convection: In convection, heat transfer occurs through the movement of fluid (liquid or gas), carrying heat from one place to another. Convection can be natural (due to density differences causing fluid movement) or forced (induced by external means like a fan or pump). Fourier's law does not directly apply to convection.
• Radiation: Radiation is the transfer of heat through electromagnetic waves, such as infrared radiation. It does not require a medium for propagation and can occur in vacuum. While Fourier's law describes conductive heat transfer, it does not directly apply to radiation.