The temperature of the cold junction of thermocouple is 0°C and the temperature of hot junction is T^o C. The emf is E = 16T - 0.04T² µV. The inversion temperature T_f is

• 300^o C

• 200^o C

• 500^o C

• 400^o C

The temperature of a gas is raised from 27° C to 927° C. The root mean square speed

• gets halved

• gets doubled

• is $\left(\sqrt{\frac{927}{27}}\right)$ times the earlier value

• remains the same

Two different isotherms representing the relationship between pressure p and volume V at a given temperature of the same ideal gas are shown for masses m₁ and m₂ , then

• Nothing can be predicted

• m₁ < m₂

• m₁ = m₂

• m₁ > m₂

1 mole of H₂ gas is contained in a box of volume V  = 1.00 m³  at  T = 300 K. The gas is heated to a temperature of  T = 3000 K  and the gas gets converted to a gas of hydrogen atoms. The final pressure would be (considering all gases to be ideal)

• same as the pressure initially

• 2 times the pressure initially

• 10 times the pressure initially

• 20 times the pressure initially

Degree of freedom for polyatomic gas

• ≥ 4

• ≥5

• ≥6

• ≥7

Assertion: Vibrational energy of diatomic molecule corresponding to each degree of  freedom is  k_B T.

Reason:  For every molecule, vibrational degree of freedom is 2.

• 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 correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false.

67.

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

           

• $\frac{3}{4}$ ρ₀

• $\frac{3}{2}$ ρ₀

• $\frac{4}{3}$ ρ₀

• 2ρ₀

Two balloons are filled, on with pure He gas and other by air, respectively. If the pressure and temperature of these balloons arc same then the number of molecules per unit volume is

• more in the He filled balloon

• same in both balloons

• more in air filled balloon

• in the ratio of 1 : 4

Assertion:  The root mean square and most probable speeds of the molecules in a gas are the same. 

Reason:  The Maxwell distribution for the speed of molecules in a gas is symmetrical.

• If both assertion and reason are true and reason is the correct explanation of the assertion

• If both assertion and reason are true but reason is not the correct explanation of the assertion

• If assertion is true, but reason is false

• Both assertion and  reason are false statements

v_rms , v_av  and v_mp are root mean square, average and most probable speeds of molecules of a gas obeying Maxwellian velocity distribution. Which of the following statements is correct?

• v_rms <  v_av  < v_mp

• v_rms > v_av >  v_mp

• v_mp > v_rms > v_av

• v_mp > v_rms > v_av