Question

The degrees of freedom of a molecule of a triatomic gas are

A. 2
B. 4
C. 6  
D. 8
Answer :   6
Solution :
The molecule of a triatomic gas has a tendency of rotating about any of three coordinate axes. So, it has 6 degrees of freedom, 3 translational and 3 rotational. At high enough temperature a triatomic molecule has 2 vibrational degree of freedom. But as temperature requirement is not given, so we answer simply by assuming triatomic gas molecule at room temperature.
Thus, $$f = 6$$
Thermodynamics mcq solution image
(3 translational +3 rotational) at room temperature.

Releted MCQ Question on
Heat and Thermodynamics >> Thermodynamics

Releted Question 1

An ideal monatomic gas is taken round the cycle $$ABCDA$$   as shown in the $$P - V$$  diagram (see Fig.). The work done during the cycle is
Thermodynamics mcq question image

A. $$PV$$
B. $$2PV$$
C. $$\frac{1}{2}PV$$
D. zero
Releted Question 2

If one mole of a monatomic gas $$\left( {\gamma = \frac{5}{3}} \right)$$  is mixed with one mole of a diatomic gas $$\left( {\gamma = \frac{7}{5}} \right)$$  the value of $$\gamma $$ for mixture is

A. 1.40
B. 1.50
C. 1.53
D. 3.07
Releted Question 3

A closed compartment containing gas is moving with some acceleration in horizontal direction. Neglect effect of gravity. Then the pressure in the compartment is

A. same everywhere
B. lower in the front side
C. lower in the rear side
D. lower in the upper side
Releted Question 4

A gas mixture consists of 2 moles of oxygen and 4 moles of argon at temperature $$T.$$ Neglecting all vibrational modes, the total internal energy of the system is

A. $$4\, RT$$
B. $$15\, RT$$
C. $$9\, RT$$
D. $$11\, RT$$

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