Pressure versus temperature graph of an ideal gas is as shown in figure. Density of the gas at point A is ρ0 Density at point B will be
ρ0
ρ0
ρ0
2ρ0
The latent heat of vaporisation of a substance is always
greater than its latent heat of fusion
greater than its latent heat of sublimation
equal to its latent heat of sublimation
less than its latent heat of fusion
A.
greater than its latent heat of fusion
Heat of vaporization: The heat of vaporization of water is defined as the amount of heat needed to turn 1 g of liquid into vapor.
Heat of fusion:- It is the energy needed to one gram of a liquid to vaporize ( boil ) without a change in pressure.
The energy required to completely separate the molecules ( in case of vaporization), i.e to convert the liquid into gas, is much greater than if you were just to reduce their separation, solid to liquid separation, solid to liquid. Hence the reason is why the latent heat of vaporization is greater than the latent heat of fusion. More energy is needed to completely separate molecules having large distance from each other.
A reversible engine converts one-sixth of the heat input into work. When the temperature of the sink is reduced by 62°C, the efficiency of the engine is doubled. The temperatures of the source and sink are
99oC, 37oC
80oC, 37oC
95oC, 37oC
90oC, 37oC
A liquid is kept in a cylindrical vessel which is being rotated about a vertical axis through the centre of the circular base. If the radius of the vessel is r and angular velocity of rotation is w, then the difference in the heights of the liquid at the centre of the vessel and the edge is
A capillary tube of radius r is immersed in water and water rises in it to a height h. The mass of water in the capillary tube is 5 g. Another capillary tube of radius 2 r is immersed in water. The mass of water that will rise in this tube is
2.5 g
5.0 g
10 g
20 g
Five sinusoidal waves have the same frequency 500 Hz but their amplitudes are in the ratio 2 : and their phase angles 0, respectively. The phase angle of resultant wave obtained by the superposition of these five waves is
30o
45o
60o
90o
The second overtone of an open pipe has the same frequency as the first overtone of a closed pipe 2 m long. The length of the open pipe is
8 m
4 m
2 m
1 m
Let T1 and T2 be the time periods of springs A and B when mass M is suspended from one ·end of each spring. If both springs are taken in series and the same mass M is suspended from the series combination, the time period is T then
T1 + T2 +T3
T2 =
Assertion: Water kept in an open vessel will quickly evaporate on the surface of the moon.
Reason: The temperature at the surface of the moon is much higher than boiling point of water.
If both assertion and reason are true and reason is the correct explanation of assertion.
If both assertion and reason are true but reason is not the correct explanation of assertion.
If assertion is true but reason is false.
If both assertion and reason are false.