Q1: A black body when hot, emits heat radiation of __________ wavelengths.

ANS:C - all

When a black body is hot, it emits electromagnetic radiation across a wide range of wavelengths. This phenomenon is known as black-body radiation. According to Planck's law, the intensity of radiation emitted by a black body at a given wavelength is determined by its temperature. As the temperature increases, the intensity of radiation increases across all wavelengths. This results in a continuous distribution of radiation across the entire electromagnetic spectrum. This emission spectrum covers all possible wavelengths, from infrared to visible light to ultraviolet and beyond. It is not limited to specific wavelengths but rather spans a broad range. Therefore, when a black body is hot, it emits heat radiation of all wavelengths. This characteristic of black-body radiation is fundamental to various fields such as thermal physics, astrophysics, and spectroscopy, and it plays a crucial role in understanding the behavior of thermal systems and astronomical objects.