NEET Practice Questions - Physics - Kinetic Theory of Gases

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    Kinetic Theory of Gases

An isolated system

(A) is a specified region where transfers of energy and mass takes place

(B) is a region of constant mass and only energy is allowed to close the boundaries

(C) is one in which mass within the system is not necessarily constant.

(D) cannot transfer either energy of mass to or from the surroundings.

The pressure and temperature of two different gases is P and T having the volume V for each. They are mixed keeping the same volume and temperature, the pressure of the mixture will be [Pb. PMT 1997, 98; DPMT 1999; MH CET 2003] la) P/2 h) P (d) 4P (c) 2P

If the mean free path of atoms is doubled then the pressure of gas will become (a) P/4 (c) P/8 IRPMT 2000] (b) P/2 (d) P

A diatomic molecule has how many degrees of freedom [Pb. PET 2000] (a) 3 (c) 5 (b) 4 (d) 6

A gas mixture consists of 2 moles of O2 and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total internal energy of the system is (a) 4RT (c) 9RT (b) 15R1 (d) 11RT

Which of the following relations is correct for root mean square speed of a gas at temperature T?

(A) Vr.m.s=3 kTm    (B)Vr.m.s=8 kTm π

(C) Vr.m.s=2 kTm    (D) Vr.m.s=m3 k T

Where k= Bolzmann constant,

m= mass of a molecule.

A thermally insulated piston divides a con- tainer ia two compartments. Volume, tem- perature and pressure in the right compart- ment are 2 V, T and 2P, while in the left com partment the respective values are V, T and P. If the piston can slide freely, then in the final equilibrium position, the volume of right hand compartment will be (e) 3V 5 (A) V gv 12V

The graph which represents the variation of mean kinetic energy of molecules with temperature t°C is? toc toC EA toC toC

Gas at a pressure po is contained in a ves- sel. If the masses of all the molecules are halved and their speeds doubled, the re- sulting pressure p will be equal to P2 (A) 4 Po (B) 2 Po (C) Po (D)

Vrms,Vav,Vmp are rrot mean square, averageand most probable speeds of molecules of a gas obeying Maxwellian velocity distribution. Which of the following statements is correct:

1. Vrms<Vav<Vmp

2. Vrms>Vav>Vmp

3. Vrms < Vav>Vmp

4. Vavg>Vrms<Vmp