Statement 1 : The temperature of gas continuously increases. Statement 2 : According to first law of thermodynamics dQ = dU + dW

Question

Each of these questions contains two statements: Statement-1(Assertion) and Statement-2 (Reason). Choose the correct answer (ONLY ONE option is correct) from the following -

(a) Statement-1 is false, Statement-2 is true. 

(b) Statement-1 is true, Statement-2 is true; Statement-2 is a correct explanation for Statement-1. 

(c) Statement-1 is true, Statement-2 is true; Statement-2 is not a correct explanation for Statement-1. 

(d) Statement-1 is true, Statement-2 is false. 

This question contains Statement-1 and Statement-2. Of the four choices given after the statements, choose the one that best describes the two statements.

Gas in cylinder with light piston is slowly heated till all the mercury spils over.  (P_atm = 76cm of Hg column)

Statement 1 : The temperature of gas continuously increases. 

Statement 2 : According to first law of thermodynamics dQ = dU + dW where symbols have their usual meaning.

Answer 1

Correct option: (a) Statement-1 is false, Statement-2 is true.

Explanation:

Initial condition

Volume = 76cm × A

Pressure = (76 + 76) dg = 152dg

Final condition

Volume = 152 cm × A

Pressure = 76dg

∴ P₁V₁ = P₂V₂

∴ Both points lie on the same isothermal line i.e. both have same T