A. Increase the heat loss
B. Decrease heat loss and will have no effect beyond that
C. Decrease heat flux
D. Reduce convection heat loss compared to conduction heat less
Related Mcqs:
- What is the critical radius of insulation (cms) for a metallic cylinder, if the convective heat transfer co-efficient with the ambient atmosphere is 5 W/m2. °K? Thermal conductivity of metal and insulation material are 40 and 0.1 W/m.°K respectively ?
A. 2
B. 8
C. 10
D. 40 - _______________ number determines whether the fluid flow in an open channel is super-critical, critical or sub-critical ?
A. Mach
B. Reynolds
C. Froude
D. Weber - Heat flow across a hollow sphere of inner radius ‘r1’ and outer radius ‘r2’ is directly proportional to__________________?
A. (r2 – r1)/r1. r2
B. r1. r2/(r2 – r1)
C. (r2 + r1)/r1. r2
D. r1. r2/(r2 + r1) - Insulation of liquid surface can be achieved by _____________ on top of its surface?
A. Floating hollow polypropylene spheres
B. Spraying alumina powder
C. Putting cement
D. None of these - Maximum heat dissipation occurs from a steel wire (k = 0.5 W/m. k) of 15 mm diameter exposed to air (h = 20W/m2 .k), when the insulation thickness is ________________ mm?
A. 15
B. 25
C. 10
D. 30 - High speed steel tools retain their hardness upto a temperature of __________________ °C?
A. 500
B. 750
C. 900
D. 1100 - Minimum temperature upto which water can be theoretically cooled down in the cooling tower by evaporative cooling is equal to the ______________ temperature of air?
A. Wet bulb
B. Dry bulb
C. Saturation
D. Dew point - The following thermocouple may be used for measuring temperature upto 1873°K__________________?
A. Chromel-alumel
B. Copper-constantan
C. Platinum-platinum rhodium
D. Iron-constantan - _____________ is the process of coating the surface of steel with aluminium oxide, thereby imparting it increased resistance to corrosion & oxidation upto a temperature of 700°C ?
A. Veneering
B. Galvanising
C. Electroplating
D. Calorising - Two wires of the same radius & material having length in the ratio of 1 : 2 are stretched by the same force. The strain produced in the two wires will be in the ratio of__________________?
A. 1 : 1
B. 1 : 2
C. 2 : 1
D. 1 : 4
