|
State and prove Stefan-Boltzmann law
|
|
0
|
3333
|
August 22, 2016
|
|
Derive the Newton's law of cooling from Stefan's law
|
|
0
|
10498
|
August 22, 2016
|
|
Find the coefficient of thermal conductivity
|
|
0
|
3685
|
August 22, 2016
|
|
What is conduction ? Give an expression for thermal conductivity. Define coefficient of thermal conductivity
|
|
0
|
3863
|
August 22, 2016
|
|
A man, the surface area of whose skin , is sitting in a room where air temperature is 20°C. If his skin temperature is 28°C and emissivity of his skin equals 0.97, find the rate at which his body loses heat
|
|
0
|
1462
|
August 22, 2016
|
|
Determine the surface area of the filament of a 100 W incandescent lamp radiating out its labelled power at 3000 K
|
|
0
|
1310
|
August 22, 2016
|
|
A brass boiler has a base area 0.15 m2 and thickness 1.0 cm. It boils water at the rate of 6.0 kg min*1 when placed on a gas stove. Estimate temperature of the part of the same in contact with the boiler
|
|
0
|
1453
|
August 22, 2016
|
|
Ratio of coefficient of thermal conductivity of two different materials is 3:2. What should be the ratio of their lengths to have same thermal resistance of the two rods of these materials of equal thickness?
|
|
0
|
1908
|
August 22, 2016
|
|
Stainless steel cooking pans are preferred with extra copper bottom. Why?
|
|
0
|
3830
|
August 22, 2016
|
|
Two rods A and B are of equal lengths. Each rod has its ends at temperature T1 and T2. What is the condition that will ensure equal rates of flow of heat through the rods A and B?
|
|
0
|
2704
|
August 22, 2016
|
|
Why do birds swell their feathers in winter?
|
|
0
|
7398
|
August 22, 2016
|
|
During winter, the metallic handle of a wooden door appears colder than the door itself, though both are at same temperature. Why?
|
|
0
|
2200
|
August 22, 2016
|
|
What is difference in temperature total rate of heat transfer and equivalent thermal resistance when two conductors are placed on the side of each other with ends at the same reservoirs of heat?
|
|
0
|
391
|
August 22, 2016
|
|
Give the expression for the net energy radiated per second
|
|
0
|
436
|
August 22, 2016
|
|
What is radiation?
|
|
0
|
587
|
August 22, 2016
|
|
What is convection?
|
|
0
|
664
|
August 22, 2016
|
|
How does a blanket prevent ice from melting?
|
|
0
|
573
|
August 22, 2016
|
|
How do wire gauges help in uniform heating?
|
|
0
|
407
|
August 22, 2016
|
|
Why are woollen clothes felt warmer than cotton clothes?
|
|
0
|
478
|
August 22, 2016
|
|
Why are cooking utensils made of metals of high thermal conductivity?
|
|
0
|
572
|
August 22, 2016
|
|
Why do two layers of cloth of equal thickness provide warmer covering than a single layer of cloth of double the thickness?
|
|
0
|
1792
|
August 22, 2016
|
|
Why are houses near north pole made with double walls of ice blocks?
|
|
0
|
430
|
August 22, 2016
|
|
Why are the bottoms of cooking vessels painted black?
|
|
0
|
478
|
August 22, 2016
|
|
Heat is generated continuously in an electric heater but the temperature remains constant after some time. Why?
|
|
0
|
1889
|
August 22, 2016
|
|
Answer about the following
|
|
1
|
1208
|
August 22, 2016
|
|
Derive an expression for molar heat capacity
|
|
0
|
5855
|
August 22, 2016
|
|
Show the expression for heat flow through a compound wall
|
|
0
|
2967
|
August 22, 2016
|
|
Find the relation for temperature gradient
|
|
0
|
2928
|
August 22, 2016
|
|
Derive an expression to find the specific heat with the help of calorimeter
|
|
0
|
3987
|
August 22, 2016
|
|
A body cools from 80°C to 50°C in 5 minute. Calculate the time it takes to cool from 60°C to 30°C. The temperature of the surrondings is 20°C. Ans. We know that, as per Newton's law of cooling
|
|
0
|
4383
|
August 22, 2016
|