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GATE ME 2020 National Champion Quiz (App update required to attempt this test)
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Question 1
The peak wavelength of radiation emitted by a black body at a temperature of 2000 K is 1.45 μm. If the peak wavelength of emitted radiation changes to 2.90 μm, then the temperature (in K) of the black body is___.
Question 2
In a solar assisted air conditioning system, 0.5 kg/s of ambient air at 270 K is to be preheated by the same amount of air leaving the system at 295 K. If a counter flow heat exchanger has an area of 30 m2, and the overall heat transfer coefficient is estimated to be 25 W/m2-K, then what is the effectiveness of the heat exchanger?
[Take
for air as 
]
[Take
for air as ] Question 3
The diameters of inner and outer tubes of a Double pipe heat exchanger are 24mm and 44mm. The thickness of the inner tube is;
Question 4
Steady one-dimensional heat conduction takes place across the faces 1 and 3 of a composite slab consisting of slabs A and B in perfect contact as shown in the figure, where kA, kB denote the respective thermal conductivities. Using the data as given in the figure, the interface temperature T2 (in oC. is ____
Question 5
Two cylindrical shafts A and B at the same initial temperature are simultaneously placed in a furnace. The surfaces of the shafts remain at the furnace gas temperature at all times after they are introduced into the furnace. The temperature variation in the axial direction of the shafts can be assumed to be negligible. The data related to shafts A and B is given in the following Table.
The temperature at the centerline of the shaft A reaches 400℃after two hours. The time required (in hours) for the centerline of the shaft B to attain the temperature of 400℃ is _____ .
The temperature at the centerline of the shaft A reaches 400℃after two hours. The time required (in hours) for the centerline of the shaft B to attain the temperature of 400℃ is _____ .
Question 6
Heat is generated uniformly in a long solid cylindrical rod (diameter = 10mm) at the rate of
. The thermal conductivity of the rod material is 25W/m.K. Under steady state conditions, the temperature difference between the centre and the surface of the rod is _________ °C.
. The thermal conductivity of the rod material is 25W/m.K. Under steady state conditions, the temperature difference between the centre and the surface of the rod is _________ °C. Question 7
A metallic rod (k=32 W/m°C), 10 mm in diameter and 80 mm long, with an insulated end is to be used as spine. It is exposed to surrounding with a temperature of 80°C and a heat transfer coefficient 55 W/m2°C. The temperature at the base of fin is 100°C. the fin efficiency will be
Question 8
An oven is maintained at a temperature of 625
the inner suface temperature is assumed to be 625 
also the outer wall of the oven is exposed to ambient condition of temperature 25
having heat transfer coefficient of 250 W/m2k. the wall thickness is 30 mm and heat dissipation is 10^5 watt/m2. Thermal conductivity of the material is 1000 w/mk find the temperature of the outer surface of the oven wall
the inner suface temperature is assumed to be 625 also the outer wall of the oven is exposed to ambient condition of temperature 25 having heat transfer coefficient of 250 W/m2k. the wall thickness is 30 mm and heat dissipation is 10^5 watt/m2. Thermal conductivity of the material is 1000 w/mk find the temperature of the outer surface of the oven wallQuestion 9
A counter flow double pipe heat exchanger using superheated steam is used to heat water at the rate of 10500 kg/h. The steam enters the heat exchanger at 180 °C and leaves at 130 °C. The inlet and exit temperatures of water are 30 °C and 80 °C respectively. If overall heat transfer coefficient from steam to water is 814 W/m2 °C. The heat transfer area is
Question 10
Water is heated from 30 °C to 60 °C by steam condensing at 120 °C. If water flow rate remains constant but its inlet temperature drops to 25 °C, then the new outlet temperature is _________ °C.
Question 11
An infinitely long furnace of 0.5 m × 0. 4 m cross-section is shown in the figure below. Consider all surfaces of the furnace to be black. The top and bottom walls are maintained at temperature T1 = T3 = 927℃while the side walls are at temperature T2 = T4 = 527℃. The view factor, F1-2 is 0.26. The net radiation heat loss or gain on side 1 is_________ W/m. Stefan-Boltzmann constant = 5.67 × 10−8 W/m2‐K4
Question 12
Consider a hemispherical furnace of diameter D = 5 m with a flat base. The dome of the furnace is black, and the base has an emissivity of 0.7. The base and dome of the furnace are maintained at uniform temperature of 400K and 1000K, respectively, the net rate of radiation heat transfer from the dome to the base surface during steady operation is ____________ kW.
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