For a radiated body, the temperature of 313 K is given. Calculate the wave length (in μm) at which monochromatic emissive power is maximum?
Question 2
A refrigerator system having COP one third of the Carnot cycle operating between temperature -23oC and 27oC. If it removes 1200 kJ/min heat from -23oC. How much heat is rejected to 27oC?
Question 3
Consider a gray opaque surface at 0oC in an environment at 25oC. The surface has an emissivity of 0.8. If the radiation incident on the surface is 240 W/m2, the radiosity of the surface is ___________.
Question 4
Ammonia is one of the oldest refrigerants, which is still used widely, because:
Question 5
A furnace is made of material whose wall of thickness 0.2 m and conductivity 0.4 W/mk. What is the thickness if it is replaced by a layer of another material of conductivity 0.8 W/mk under the same heat loss per unit area and same temperature drop ?
Question 6
In reciprocating compressor, clearance is provided
(a) To improve the volumetric efficiency of the compressor.
(b) To accommodate valves
(c) To account for thermal expansion due to temperature variation
(d) To reduce power consumption of compressor
Question 7
If air enter the cooling coil of surface temperature 10oC with mass flow rate 20 kg/s.
Inlet condition of air. 30oC DBT, specific humidity. ω1 = 0.0182, enthalpy, h1 = 75 kJ/kg of dry air.
Outlet condition of air. 20oC DBT, specific humidity. ω2 = 0.011, enthalpy, h2 = 48 kJ/kg of dry air.
Find the rate of water vapour condensed in (kg/min)
Question 8
Consider two rods A, B of the same material and subjected to equal axial load. The rod A is of uniform cross-section with diameter d, and the rod B taper uniformly from diameter d at one end to diameter d/2 at other end. The ratio of elongation of rod A to elongation of rod B will be __________.
Question 9
A specimen with a 12.5 mm diameter and 50 mm gauge length is used in a tension test of an aluminium alloy. At load of 250N the total elongation is 2mm. True stress and true strain are.
Question 10
An Otto cycle with compression ratio of 6 have 800kJ/kg of heat energy supplied in constant volume heat addition process. What is work done(kJ) by burning per kg of fuel?
