Thermal Properties of Matter
(Specific heat of water = 4.2 J/g/°C Specific heat of Ice = 2.1 J/g/°C Heat of fusion of water at 0°C = 334 J/g)
(Specific heat of water is 4.2 kJ kg–1 K–1 and the density of water is 1000 kg m–3)
(i) Sequentially keeping in contact with 2 reservoirs such that each reservoir supplies same amount of heat.
(ii) Sequentially keeping in contact with 8 reservoirs such that each reservoir supplies same amount of heat.
In both the cases body is brought form initial temperature 100°C to final temperature 200°C. Entropy change of the body in the two cases respectively is:
Consider the partition to be rigidly fixed so that it does not move. When equilibrium is achieved, the final temperature of the gases will be
Now, consider the partition to be free to move without friction so that the pressure of gases in both compartments is the same. Then, total work done by the gases till the time they achieve equilibrium will be
[Take specific heat of water = 1 cal g−1 °C−1 and latent heat of steam = 540 cal g−1]
Reason Air can be heated only by convection.
Two rectangular blocks, having identical dimensions, can be arranged either in configuration I or in configuration II as shown in the figure. One of the blocks has thermal conductivity κ and the other 2κ. The temperature difference between the ends along the x-axis is the same in both the configurations. It takes 9 s to transport a certain amount of heat from the hot end to the cold end in the configuration I. The time to transport the same amount of heat in the configuration II is
If a piece of metal is heated to temperature θ and then allowed to cool in a room which is at temperature θ0, the graph between the temperature T of the metal and time t will be closest to:
The figure below shows the variation of specific heat capacity (C) of a solid as a function of temperature (T). The temperature is increased continuously from 0 to 500 K at a constant rate. Ignoring any volume change, the following statement(s) is (are) correct to a reasonable approximation.
Liquid oxygen at 50K is heated to 300 K at constant pressure of 1 atm. The rate of heating is constant. Which one of the following graphs represents the variation of temperature with time ?
A composite block is made of slabs A, B, C, D and E of different thermal conductivities (given in terms of a constant K) and sizes (given in terms of length, L) as shown in the figure. All slabs are of same width. Heat ‘Q’ flows only from left to right through the blocks. Then in steady state
Reason : Air surrounding the fire conducts, more heat upward.
Reason : The thermal radiations require no medium for propagation.
A piece of ice (heat capacity = 2100m J kg-1oC-1 and latent heat =) of mass m grams is at −5oC at atmospheric pressure. It is given 420 J of heat so that the ice starts melting. Finally when the ice-water mixture is in equilibrium, it is found that 1gm of ice has melted. Assuming there is no other heat exchanger in the process, the value of m is
Two spherical bodies A (radius 6cm) and B (radius 18cm) are at temperature T1 and T2, respectively. The maximum intensity in the emission spectrum of A is at 500 nm and in that of B is at 1500 nm. Considering them to be black bodies, what will be the ratio of the rate of total energy radiated by A to that of B?
If S represents specific heat and L represents latent heat of liquid, then
Cv and Cp denote the molar specific heat capacities of a gas at constant volume and constant pressure respectively. Then
A metal rod of length has its one end in ice at 0°C, and the other end in water at 100°C. If a point on the rod is maintained at 400°C, then it is found that equal amounts of water and ice evaporate and melt per unit time. The latent heat of evaporation of water is and latent heat of melting of ice is If the point is at a distance of from the ice end find the value of [Neglect any heat loss to the surrounding.]
Column I contains a list of processes involving expansion of an ideal gas. Math this with Column II describing the thermodynamic change during this process. Indicate your answer by darkening the appropriate bubbles of the matrix given in the ORS.
|Column I||Column II|
An insulated container has two chambers separated by a valve. Chamber I contains an ideal gas and the Chamber II has vacuum. The valve is opened
|(p)||The temperature of the gas decreases|
An ideal monoatomic gas expands to twice its original volume such that its pressure , where V is the volume of the gas
|(q)||The temperature of the gas increases or remains constant.|
An ideal monoatomic gas expands to twice its original volume such that its pressure , Where V is its volume
|(r)||The gas loses heat|
An ideal monoatomic gas expands such that its pressure P and volume V follows the behaviour shown in the graph
|(s)||The gas gains heat|
Given: Lfusion = 80 cal/g = 336 J/g; Lvaporisation = 540 cal/g = 2268 J/g
Sice = 2100 J/kg; K = 0.5 cal/gK and Swater = 4200 J/kg; K = 1 cal /gK
(a) Find the radiation loss to the surroundings in J/m2/s if the temperature of the upper surface of disc is 127°C and the temperature of the surrounding is 27°C.
(b) Also, find the temperature of the circulating oil. Neglect the heat loss due to convection.
(A) initially, it is the darkest body and later, it is the brightest
(B) it is the darkest body at all times
(C) it cannot be distinguished at all times
(D) initially, it is the darkest body and later, it cannot be distinguished