In ________ process heat is transmitted without any medium. 

The correct answer is Radiation.

Key Points

• Radiation is the process of heat transfer through electromagnetic waves without requiring any medium.
• This type of heat transfer can occur in a vacuum, where there is no medium, such as in space.
• The Sun transfers heat to Earth through radiation, demonstrating the principle of heat transfer without any medium.
• Radiation involves the emission of energy as electromagnetic waves or as moving subatomic particles, particularly high-energy particles that cause ionization.

Additional Information

• Conduction: The process of heat transfer through direct contact between molecules within a material.
• Convection: The process of heat transfer through the movement of fluids (liquids or gases) caused by molecular motion.
• Reflection: The process by which light or heat bounces off a surface without being absorbed.
• Electromagnetic Spectrum: Radiation spans a broad range of wavelengths and includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.