FIRST LAW OF THERMODYNAMICS 217
dharm
/M-therm/Th4-7.pm5- The net work done per kg of gas in a polytropic process is equal to
(a)p 1 v 1 loge vv^2
1
(b)p 1 (v 1 – v 2 )(c)p 2 v 2 vv^1
2FHG − IKJ (d)
pv p v
n11 2 2
1−
−(e) pv^21 n−−pv 122.- Steady flow occurs when
(a) conditions do not change with time at any point
(b) conditions are the same at adjacent points at any instant
(c) conditions change steadily with the time
(d)GHF∂∂vtIKJ is constant.
- A reversible process requires that
(a) there be no heat transfer (b) newton’s law of viscosity be satisfied
(c) temperature of system and surroundings be equal
(d) there be no viscous or coloumb friction in the system
(e) heat transfer occurs from surroundings to system only. - The first law of thermodynamics for steady flow
(a) accounts for all energy entering and leaving a control volume
(b) is an energy balance for a specified mass of fluid
(c) is an expression of the conservation of linear momentum
(d) is primarily concerned with heat transfer
(e) is restricted in its application to perfect gases. - The characteristic equation of gases pV = mRT holds good for
(a) monoatomic gases (b) diatomic gas
(c) real gases (d) ideal gases
(e) mixture of gases. - A gas which obeys kinetic theory perfectly is known as
(a) monoatomic gas (b) diatomic gas
(c) real gas (d) pure gas
(e) perfect gas. - Work done in a free expansion process is
(a) zero (b) minimum
(c) maximum (d) positive
(e) negative. - Which of the following is not a property of the system?
(a) Temperature (b) Pressure
(c) Specific volume (d) Heat
(e) None of the above. - In the polytropic process equation pvn = constant, if n = 0, the process is termed as
(a) constant volume (b) constant pressure
(c) constant temperature (d) adiabatic
(e) isothermal. - In the polytropic process equation pvn = constant, if n is infinitely large, the process is termed as
(a) constant volume (b) constant pressure
(c) constant temperature (d) adiabatic
(e) isothermal.