# Thermo Dynamics

Thermo Dynamics
Question:-
Option (A)
There is no energy or mass transfer across the boundary
Option (B)
There is no mass transfer, but mass transfer exists
Option (C)
There is no energy transfer, but mass transfer exists
Option (D)
Both energy and mass transfer take place across the boundary, but the mass transfer is controlled by values
Correct Option:
B
Question Solution:
A closed system (also known control mass) consist of fixed amount of mass and no mass can cross its boundary but energy in the from of heat and work can cross the boundary and the volume of closed system does not have to be fixed if energy is not allowed to cross the boundary that system is called isolated system
Question:-
Option (A)
-400
Option (B)
-200
Option (C)
200
Option (D)
400
Correct Option:
B
Question Solution:
Since control man (so case of closed system) intercept of path on X-axis is the work done by the process

W = area of ΔA 12 + area of NA2CB
W = (1/2)x (3-1)x 200 + 100 x (3-1)
= 200+200=400kJ
W = (1/2)(300-100) x 2 + 100 x 2
= 200+200 = 400 kJ
\ From 1 ® 2
U1 + Q = U2 + W
U1 - U2 = W –Q = 400 – 200 = 200 kJ
From 2 ® 1
Work done will be same
Since adiabatic so Q = 0
U2 + Q = U1 + W
W = U2 - U1 =-(U1-U2) =- 200 KJ
Question:-
Option (A)
1 alone
Option (B)
3 alone
Option (C)
1 and 2
Option (D)
None of 1, 2 and 3
Correct Option:
C
Question Solution:
hcarnot = 1 –(T2/T1)= 50.179 %
hengine = {(Q1-Q2)/Q1} = 50.8%
hengine ² hcarnot = hrev
Question:-
Option (A)
1.5
Option (B)
0.5
Option (C)
2
Option (D)
1
Correct Option:
C
Question Solution:
COP = (Desired effect / Work read) = (600 / (600-300)) = 2