ME GATE 2009 - Online Test
Q1. If a closed system is undergoing an irreversible process, the entropy of the system
Answer : Option D
Explaination / Solution:
No Explaination.
Q2. A coolant fluid at 30°C flows over a heated flat plate maintained at a constant temperature of 100°C. The boundary layer temperature distribution at a given location on the plate may be
approximated as T = 30 + 70 exp (-y) where y (in m) is the distance normal to the plate and T is
in °C. If thermal conductivity of the fluid is 1.0W/m2K, the local convective heat transfer coefficient
(in W/ K) at that location will be
Answer : Option B
Explaination / Solution:
No Explaination.
Q3. A frictionless piston-cylinder device contains a gas initially at 0.8MPa and 0.015 m3. It expands
quasi-statically at constant temperature to a final volume of 0.030 m3. The work output (in kJ)
during this process will be
Answer : Option A
Explaination / Solution:
No Explaination.
Q4. In an ideal vapour compression refrigeration cycle, the specific enthalpy of refrigerant (in kJ/kg)
at the following states is given as:
Inlet of condenser: 283
Exit of condenser: 116
Exit of evaporator: 232
The COP of this cycle is
Answer : Option A
Explaination / Solution:
No Explaination.
Q5. A compressor undergoes a reversible, steady flow process. The gas at inlet and outlet of the
compressor is designated as state 1 and state 2 respectively. Potential and kinetic energy changes
are to be ignored. The following notation are used:
v = specific volume and P = pressure of the gas. The specific work required to be supplied to the
compressor for this gas compression process is
Answer : Option B
Explaination / Solution:
No Explaination.
Q6. Consider steady, incompressible and irrotational flow through a reducer in a horizontal pipe
where the diameter is reduced from 20cm to 10cm. The pressure in the 20cm pipe just upstream
of the reducer is 150 kPa. The fluid has a vapour pressure of 50kPa and a specific weight of 5
kN/m3. Neglecting frictional effects, the maximum discharge (in m3/s) that can pass through the
reducer without causing cavitation is
Answer : Option B
Explaination / Solution:
No Explaination.
Q7. In a parallel flow heat exchanger operating under steady state, the heat capacity rates (product of
specific heat at constant pressure and mass flow rate) of the hot and cold fluid are equal. The hot
fluid, flowing at 1 kg/s with Cp= 4kJ/kgK, enters the heat exchanger at 102°C, while the cold fluid
has an inlet temperature of 15°C. The overall heat transfer coefficient for the heat exchanger is
estimated to be 1kW/m2K and the corresponding heat transfer surface area is 5m2. Neglect heat
transfer between the heat exchanger and the ambient. The heat exchanger is characterized by the
following relation: 2ε = 1 - exp(-2NTU). The exit temperature (in °C) for the cold fluid is
Answer : Option B
Explaination / Solution:
No Explaination.
Q8. In an air-standard Otto cycle, the compression ratio is 10. The condition at the beginning of the
compression process is 100kPa and 27oC. Heat added at constant volume is 1500 kJ/kg, while
700 kJ/kg of heat is rejected during the other constant volume process in the cycle. Specific gas
constant for air = 0.287kJ/kgK. The mean effective pressure (in kPa) of the cycle is
Answer : Option D
Explaination / Solution:
No Explaination.
Q9. An irreversible heat engine extracts heat from a high temperature source at a rate of 100kW and
rejects heat to a sink at a rate of 50kW. The entire work output of the heat engine is used to drive a
reversible heat pump operating between a set of independent isothermal heat reservoirs at 17oC
and 75oC. The rate (in kW) at which the heat pump delivers heat to its high temperature sink is
Answer : Option C
Explaination / Solution:
No Explaination.
Q10. You are asked to evaluate assorted fluid flows for their suitability in a given laboratory application.
The following three flow choices, expressed in terms of the two-dimensional velocity fields in the
x-y plane, are made available.
P. u = 2y, v = -3x; Q. u = 3xy, v = 0; R. u = -2x, v = 2y
Which flows(s) should be recommended when the application requires the flow to be
incompressible and irrotational?
Answer : Option D
Explaination / Solution:
No Explaination.
