What is the emissivity of a black body ?

1.	What is the emissivity of a black body ?
A.	1
B.	0¬†
C.	0.9
D.	0.5
Answer» B. 0¬†

Discussion

No Comment Found

Related MCQs

Hot water (0.01 m /min) enters the tube side of a counter current shell and tube heat exchanger at 80°C and leaves at 50°C. Cold oil (0.05 m/min) of density 800 kg/m and specific heat of 2 kJ/kg.K enters at 20°C. The log mean temperature difference in °C is approximately
A process stream of dilute aqueous solution flowing at the rate of10 Kg.s is to be heated. Steam condensate at 95°C is available for heating purpose, also at a rate of 10 Kg.s. A 1 - 1 shell and tube heat exchanger is available. The best arrangement is
A 10 cm dia steam pipe, carrying steam at 180°C, is covered with an insulation (conductivity = 0.6 W/m.°C). It losses heat to the surroundings at 30°C. Assume a heat transfer co-efficient of 0.8 W/m.°C for heat transfer from surface to the surroundings. Neglect wall resistance of the pipe and film resistance of steam. If the insulation thickness is 2 cms, the rate of heat loss from this insulated pipe will be
In the equation = Δ; Δ is
In Joule's experiment, an insulated container contains 20 kg of water initially at 25°C. It is stirred by an agitator, which is made to turn by a slowly falling body weighing 40 kg through a height of 4 m. The process is repeated 500 times. The acceleration due to gravity is 9.8 ms. Neglecting the heat capacity of agitator, the temperature of water (in °C) is
The heat flux (from outside to inside) across an insulating wall with thermal conductivity, K= 0.04 W/m.°K and thickness 0.16m is 10 W/m. The temperature of the inside wall is - 5°C. The outside wall temperature is
Steam consumption in kg/hr in case of an evaporator is given by (where, & are capacity the economy of the evaporator respectively)
With the increase of temperature, the Col-burn factor
Minimum recommended baffle spacing in a shell and tube heat exchanger is about (where, = shell diameter)
The equation, , corrosponds to __________ analogy.

What is the emissivity of a black body ?

Discussion

No Comment Found

Related MCQs

Reply to Comment