An ideal gas is taken through the cycle A ➔ B ➔ C ➔ A, as shown in the figure. If the net heat supplied to the gas in the cycle is 5J, the work done by the gas in the process. C ➔ A is :

• -5 J

• -10 J

• -15 J

• -20 J

In an adiabatic process, the state of a gas is changed from P₁, V₁, T₁ to P₂, V₂, T₂. Which of the following relation is correct?

• ${\mathrm{T}}_1{\mathrm{V}}_1^{\mathrm{\gamma }-1} ={\mathrm{T}}_2{\mathrm{V}}_2^{\mathrm{\gamma }-1}$

• ${\mathrm{P}}_1{\mathrm{V}}_1^{\mathrm{\gamma }-1} = {\mathrm{P}}_2{\mathrm{V}}_2^{\mathrm{\gamma }-1}$

• ${\mathrm{T}}_1{\mathrm{P}}_1^{\mathrm{\gamma }} = {\mathrm{T}}_2{\mathrm{P}}_2^{\mathrm{\gamma }}$

• ${\mathrm{T}}_1{\mathrm{V}}_1^{\mathrm{\gamma }} = {\mathrm{T}}_2{\mathrm{V}}_2^{\mathrm{\gamma }}$

193.

If 300 ml of a gas at 27° C is cooled to 7° C at constant pressure, then its final volume will be

• 540 mL

• 350 mL

• 280 mL

• 135 mL

A gas at state A changes to state B through path I and II as shown in figure. The change in internal energy is ΔU₁ and ΔU₂ respectively. Then :

• ΔU₁ > ΔU₂

• ΔU₁ < ΔU₂

• ΔU₁ = ΔU₂

• ΔU₁ = ΔU₂ = 0

An ice at -50°C is to be converted into vapour at 100°C. The heat required in this process is

• 1028 calorie

• 624 calorie

• 745 calorie

• 810 calorie

An ideal gas heat engine operates in Carnot cycle between 227°C and 127$°$C. It absorbs 6 x 10⁴ cal of heat at higher temperature. Amount of heat converted into work is

• 1.2 x 10⁴ cal

• 2.2 x 10⁴ cal

• 6.0 x 10⁴ cal

• 4.8 x 10⁴ cal

The neutral temperature of a thermocouple is 300°C. What is the inversion temperature, if the temperature of cold junction is l0°C?

• 590°C

• 610°C

• 310°C

• 290°C

For adiabatic process  $\left(\mathrm{\gamma } = \frac{{\mathrm{C}}_{\mathrm{p}}}{{\mathrm{C}}_{\mathrm{V}}}\right)$

• ${\mathrm{p}}^{\mathrm{\gamma }}\mathrm{V} = \mathrm{constant}$

• ${\mathrm{Tp}}^{\mathrm{\gamma }}\mathrm{V} = \mathrm{constant}$

• ${\mathrm{pV}}^{\mathrm{\gamma }} = \mathrm{constant}$

• pV = constant

A Carnot engine works between temperature 72°C and 27°C. The efficiency of the engine is

• 70 %

• 30 %

• 0 %

• 10 %

Boyle's law is applicable for an

• adiabatic process

• isothermal process

• isobaric process

• isochoric process