Ktg and thermodynamics

Question

3. Figure shows P-T diagram for a given mass of an ideal gas for the process A→ B. During this process, density of the gas is
(1) Decreasing
(2) Increasing
(3) Constant
(4) First decreasing then increasing

4. Figure shows P-V diagram for a given mass of an ideal gas for the process 1→2. During this process temperature of the gas

(1) Decreases continuously
(2) Increases continuously
(4) First increases then decreases
(3) First decreases then increases

Answer 1

3. (3) Constant

Given, 

P-T diagram

Density of gas will be constant as from graph pressure is directly proportional to the temperature

For ideal gas PV = nRT

From this relation V is constant

\(Density = \frac {mass}{volume}\)

As mass and volume both are constant so it's density will also constant.

4. (2) Increases continuously

PV = nRT

P/V = const = K

P = KV

⇒ (KV)V = nRT

⇒ V² = CT

V_A < V_B

T_A < T_B

Increases