The thermal radiation emitted by a body is proportional to T n, where T is its absolute temperature. The value of 'n' is exactly 4 for

Related MCQs

• Stefan-Boltzmann law which describes the radiation heat transfer states that, it is proportional to (where, t = temperature in °C T = absolute temperature in ° K)
• The rate of radiant energy, which is emitted by a surface at any temperature and in small wavelength is found from the known rate of energy, which under the same condition would be emitted from a black surface by multiplying with the absorptivity. Above enunciation is known as
• All substances emit radiation, the quality and quantity depending upon the absolute temperature and the properties of the material composing the radiating body. The above statement is known as the statement of
• The total emissivity power is .defined as the total amount of radiation emitted by a black body per unit
• The variation of thermal conductivity of a metal with temperature is often correlated using an expression of the form K = K0 + at, where, K is the thermal conductivity and T is the temperature (in °K). The units of 'a' in SI system will be
• A wall has two layers A and B, each made of a different material. Both the layers have the same thickness. The thermal conductivity of material of A is twice that of B. Under the thermal equilibrium the temperature difference across the wall is 30?C. The temperature drops in layers A and B will be respectively
• The radiation heat flux from a heating element at a temperature of 800°C, in a furnace maintained at 300°C is 8 kW/m2 . The flux, when the element temperature is increased to 1000°C for the same furnace temperature is
• For gases, the thermal conductivity increases with temperature rise. For liquids, with increase in concentration, its thermal conductivity generally
• The wavelength at which the maximum monochromatic emissive power occurs for a black body, is (where, T = absolute temperature of the black body).
• Walls of a cubical oven are of thickness l, and they are made of material of thermal conductivity k. The temperature inside the oven is 100°C and the inside heat transfer coefficient is „3k/l’. If the wall temperature on the outside is held at 25°C, what is the inside wall temperature in degree centigrade?