Multiple Choice with ONE correct answer 1. A wall has two layers A and B, each made of different material. Both the layers have the same thickness.
The thermal conductivity of the material of A is twice that of B. From the following statements, concerning ideal gas at any given temperature T, select the correct one s.
Two metallic sphere S1 and S 2 are made of the same material and have got identical surface finish. The mass of S1 is thrice that of S 2.
Both spheres are heated to the same high temperature and placed in the same room having lower temperature but are thermally insulated from each other. The average translational kinetic energy and the root mean square speed of molecules in a sample of oxygen gas at K are 6. The intensity of radiation emitted by the Sun has its maximum value at a wavelength of nm and that emitted by the North star has the maximum value at nm.
If these stars behave like black bodies, then the ratio of the surface temperatures of the Sun and the North Star is [ mark] a 1. The pressure of the gas is P. It absorbs 10 4 J of heat at the higher, temperature. The ratio of the speed of sound in nitrogen gas to that in helium gas, at K is [ marks] Ans. A monoatomic ideal gas, initially at temperature T1, is enclosed in a cylinder fitted with a frictionless piston. The gas is allowed to expand adiabatically to a temperature T 2 by releasing the piston suddenly.
Starting with the same gas expands from volume V t to V 2 in three different ways. The plots of intensity versus wavelength for three black bodies at temperature T p T 2 and T 3 respectively are as shown. Their temperatures are[ marks] Ans. Each rod is of the same length. P-V plots for two gases during adiabatic processes are shown in the figure. An ideal black body at room temperature is thrown into a furnace.
While at lower temperature, a black-body absorbs all the incident radiations. It becomes the brightest of all. Option a represents the answer. The graph, shown in the adjacent diagram, represents the variation of temperature T of two bodies, x and y having same surface area, with time t due to the emission of radiation. Find the correct relation between the emissivite and absorptive powers of the two bodies.
The PT diagram for an ideal gas is shown in the figure, where AC is an adiabatic process. Find the corresponding PV diagram. Graphs b and d satisfy this condition Options a and c are therefore incorrect. This condition is certainly not satisfied in option d where AC is a straight line at constant V.
Here AC is an isochoric process. It is not an adiabatic process d is incorrect. Hence the ultimate correct process is b. Calculate the final mass of water remaining in the container.
Three discs A, B, and C having radii 2 cm, 4 cm and 6 cm respectively are coated with carbon black on their outer surfaces. The wavelengths corresponding to maximum intensity are nm, nm and nm respectively. If liquefied oxygen at 1 atmospheric pressure is heated from 50 K to K by supplying heat at constant rate, the graph of temperature vs time will be Ans. If they are connected in series then the rate is q 2. If W is the net work done by the gas in complete process which of the following is true?
Which of the following option is the correct match? In which of the following processes, heat convection does not take place primarly? For convection process, a medium is required which can move between two points to transfer heat. Bulb is almost evacuated to have no medium.
Option d represents the answer. Energy radiated per second by the body at temperature T Ans. The two ends of you have a 2liter bottle of liquid water at 0 c about how many calories are needed to heat up the wa combined system are maintained at two different temperatures. There is no loss of heat across the cylindrical surface and the system is in steady state. A real gas behaves like an ideal gas if its [] a pressure and temperature are both high b pressure and temperature are both low c pressure is high and temperature is low d pressure is low and temperature is high Ans.
Therefore real gas is behaves as ideal gas. Taking the initial temperature to be T: Three closed vessels A, B and C are at the same temperature T and contain gases which obey the Maxwellian distribution of velocities. If the average speed of the 0 2 molecules in vessel A is V1 that of the N 2 molecules in vessel B is v 2the average speed of the 0 2 molecules in vessel C is Where M is the mass of an oxygen molecule [ marks] Ans.
Select the correct statement s from the following. The piston of A is free to move,while that of B is held fixed. The same amount of heat is given to the gas in each cylinder. A black body is at a temperature of K. A vessel contains a mixture of one mole of oxygen and two moles of nitrogen at K. The ratio of the average rotational kinetic energy per 0 2 molecule to that per N 2 molecule is [ marks] a 1: A bimetallic strip is formed out of two identical strips one of copper and the other of brass.
The coefficients of linear expansion of the two metals are a c and a B. On heating, the temperature of the strip goes up by DT and the strip bends to form an arc of radius of curvature R. Initially a black body at absolute temperature T is kept inside a closed chamber at absolute temperature T 0.
Now the chamber is slightly opened to allow Sun rays to enter. It is observed that temperatures T and T 0 you have a 2liter bottle of liquid water at 0 c about how many calories are needed to heat up the wa constant. Hence the correct choices are a and d. Its pressure at A is P 0. C v and C p denote the molar specific heat capacities of a gas at constant volume and constant pressure, respectively.
C v is larger for a diatomic ideal gas than for a mono atomic ideal gas Ans. All slabs are of same width. The following question contains statement -1 assertion and statement -2 reason Of these statements, mark correct choice if a Statement — 1 and 2 are true and statement-2 is a correct explanation for statement-1 b Statement — 1 and 2 are true and statement-2 is not a correct explanation you have a 2liter bottle of liquid water at 0 c about how many calories are needed to heat up the wa statement-1 c Statement — 1 is true, statement-2 is flase d Statement — 1 is false, statement-2 is true.
The total translational kinetic energy of all the molecules of a given mass of an ideal gas is 1. The molecules of a gas collide with each other and the velocities of the molecules change due to the collision [ marks] Ans. Match the device in column I with the processes in column II. Column I contains a list of processes involving expansion of an ideal gas. Match this with Column II describing the thermodynamic change during this process.
Column II gives certain systems undergoing a process. Column I you have a 2liter bottle of liquid water at 0 c about how many calories are needed to heat up the wa changes in some of the parameters related to the system. Mechanical energy provided to the system by the moment of the piston is converted into kE of gas molecules. The average KE per molecule will decrease. Hence None of the options in column I matches. Column II given the characteristics involved in the cycle.
Match them with each of the processes given in Column I Ans. A composite rod is made by joining a copper rod, end to end, with a second rod of different material but of the same cross-section. When the composite rod is not allowed to expand by holding it between two rigid walls, it is found that the length of the two constituents do not change with the rise of temperature. Study the graph carefully and answer the following questions.
A jar contains a gas and a few drops of water at T K. The pressure in the jar is mm of Hg. The saturated vapour pressures of water at the two temperatures are 30 and 25mm of Hg.
Calculate the new pressure in the jar. The final volume of the gas is 2 litre. A solid sphere of copper of radius R and a hollow sphere of the same material of inner radius r and outer radius R are heated to the same temperature and allowed to cool in the same environment. Which of them starts cooling faster? It is then suddenly stopped. Calculate the speed v 0.
Workdone is negative as the volume in right chamber decreases. What is the new value of the pressure inside the bulbs? The volume of the connecting tube is negligible. The walls have three different layer materials.
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