Absorptivity and reflectivity of a perfect black body are respectively

Related MCQs

• Absorptivity of a perfect black body is unity. Which of the following has maximum absorptivity?
• Depending on the radiating properties, a body will be black when (where a = absorptivity, p == reflectivity, X = transmissivity.)
• If the absorptivity plus reflectivity of a body equals 1, then the body is known as
• The sum of reflectivity and absorptivity for an opaque body is equal to
• Depending on the radiating properties, a body will be white when (where a = absorptivity, p = reflectivity, x = transmissivity)
• Depending on the radiating properties, a body will be opaque when (where a = absorptivity, p = reflectivity, X = transmissivity.)
• A perfect black body is a perfect __________ of radiation.
• Two large closely spaced concentric spheres (both of which are perfect black body radiators) are maintained at temperatures of 127?C and 27?C respectively. The space in between the two spheres is evacuated. Taking Stefan Boltzmann constant as 5.67 x 108 watt m2K the rate of radiation in watts per sq. m between the two spheres is approximately
• In thermal radiation for a black body (where, ε is emissivity and α is absorptivity)
• What is the absorptivity of a black body?