A block of ice at - 10oC is slowly heated and converted to steam at 100oC. Which of the following curves represents the phenomenon qualitatively ?
The sprinkling of water reduces slightly the temperature of a closed room because :
Temperature of water is less than that of the room
Specific heat of water is high
Water has large latent heat of vaporisation
Water is bad conductor of heat
Heat current is maximum in which of the following (rods are of identical dimension) ?
Variation of radiant energy emitted by sun, filament of tungsten lamp and welding arc as a function of its wavelength is shown in figure. Which of the following options is the correct match ?
sun - T3, tungsten filament - T1, welding arc - T2
sun - T2, tungsten filament - T1, welding arc - T3
sun - T3, tungsten filament - T2, welding arc - T1
sun - T1, tungsten filament - T2, welding arc - T3
What is the difference between the two principal specific heats of 1 g of helium gas at S.T.P. ? Given molecular weight of helium = 4 and J=4.186 J cal-1 and R=8.31 J mol-1 K-1 .
0.586 cal g-1 K-1
0.496 cal g-1 K-1
0.782 cal g-1 K-1
0.576 cal g-1 K-1
Temperature of a black body increases from 327oC to 927oC, the initial energy possessed is 2 kJ. What is its final energy ?
32 kJ
320 kJ
1200 kJ
32 J
Two identical rods are connected between two containers. One of them is at 100oC and another is at 0oC. If rods are connected in parallel then, the rate of melting of ice is q1 g/sec. If they are connected in series then, the rate is q2. The ratio q2/q1 will be :
2
4
1/2
1/4
A pressure cooker reduces cooking time for food, why ?
Heat is more evenly distributed in the cooking space
The higher pressure inside the cooker crushes the food material
Cooking involves chemical changes helped by a rise in temperature
Coiling point of water involved in cooking is increased.
Heat given to a body, which raises its temperature by 1oC is :
Water equivalent
Temperature gradient
Thermal capacity
Specific heat
Wien's law states that :
T + λm = constant
λm T= constant
λm/T = constant
T4/ λm = constant
