Deck 10: Energy and Thermodynamics

Question 1

The gas laws can be used with minimum error is case of

A)wet steam
B)dry steam
C)saturated steam
D)superheated steam

Answer 1

superheated steam

Question 2

Mathematically a pure substance can be written as

A)p=f(t,v)
B)v= f(p,t)
C)t=f(p,v)
D)any of the above

Answer 2

any of the above

Question 3

A Carnot cycle operates between source & sink temperatures of 250°C & - 15°C. If the system receives 90kJ from the source then the net work transfer equals

A)30.5 kj
B)35.65 kj
C)45.54 kj
D)65.54 kj

Answer 3

45.54 kj

Question 4

Consider the following statements regarding superheating in Rankine Cycles
1) It reduces the specific steam consumption
2) It increases the dryness fraction of steam at the exhaust for the same value of condenser pressure
3) It reduces the cycle efficiency Of the these statements

A)1 & 2 are correct
B)2 & 3 are correct
C)1 & 3 are correct
D)1, 2 & 3 are correct

Question 5

Energy is a

A)point function
B)property of the system
C)extensive property
D)all of the mentioned

Question 6

The specific energy, e=E/m is an extensive property.

Question 7

(m*V*V)/2 gives the

A)macroscopic kinetic energy
B)microscopic kinetic energy
C)macroscopic potential energy
D)microscopic potential energy

Question 8

(m*g*z) gives the

A)macroscopic kinetic energy
B)microscopic kinetic energy
C)macroscopic potential energy
D)microscopic potential energy

Question 9

Which of the following types of energy can be present in molecules?

A)translational and rotational kinetic energy
B)electronic energy and vibrational energy
C)chemical energy and nuclear energy
D)all of the mentioned

Question 10

The total internal energy of the system is given by

A)u=n/?
B)u=n?
C)u=?/n
D)none of the mentioned

Question 11

In an ideal gas there are no intermolecular forces of attraction and repulsion, and the internal energy is a function of temperature only.

Question 12

Which of the following is true in regard to the energy of an isolated system?

A)dq?0
B)dw?0
C)e=constant
D)all of the mentioned

Question 13

A perpetual motion machine of first kind

A)is a fictitious machine
B)can supply mechanical work without dissipating energy
C)violates first law
D)all of the mentioned

Question 14

The limitation of the first law is

A)does not indicate the possibility of a spontaneous process proceeding in a definite direction
B)it assigns a quality to different forms of energy
C)indicates the direction of any spontaneous process
D)none of the mentioned

Question 15

Integral of dQ/T is independent of reversible path connecting between two points.

Question 16

Integral of dQ/T of a reversible path is given by

A)si-sf
B)sf-si
C)si+sf
D)-si-sf

Question 17

Entropy is a

A)path function, intensive property
B)path function, extensive property
C)point function, intensive property
D)point function, extensive property

Question 18

Specific entropy is given by( where m is the mass)

A)sm
B)m/s
C)s/m
D)none of the mentioned

Question 19

For any process which is undergone by a system

A)dq/t>=ds
B)dq/t<=ds
C)dq/t?ds
D)none of the mentioned

Question 20

For an irreversible process,

A)ds=dq/t
B)ds>dq/t
C)dsD)none of the mentioned

Question 21

For two different paths between same two points, entropy change is

A)depends on path taken
B)different
C)same
D)none of the mentioned

Question 22

For the general case, we can write

A)s2-s1<=dq/t for a path
B)s2-s1>=dq/t for a path
C)s2-s1?dq/t for a path
D)none of the mentioned

Question 23

A reversible process is performed in such a way that

A)at the conclusion of process, both system and surroundings can be restored to their initial states without producing any change
B)it should not leave any trace to show that the process had ever occurred
C)it is carried out infinitely slowly
D)all of the mentioned

Question 24

A reversible process coincides with a quasi-static process.

Question 25

Irreversibility of a process may be due to

A)lack of equilibrium during the process
B)involvement of dissipative effects
C)both of the mentioned
D)none of the mentioned