81. The gas turbine power plants have the advantages of
(a) simplicity of design and installation, high reliability, compactness, clean exhaust and low initial cost.
(b) quick starting and capability of putting to share full load in few minutes.
(c) high overall efficiency, low specific consumption and long life in comparison to that of steam power plants.
(d) both (a) and (b).
Answer: (d) both (a) and (b).
82. The main drawbacks of gas turbine power plants are
(a) low overall efficiency, noisy operation and limited unit capacity.
(b) inability of using coal or heavy residual petroleum as fuels.
(c) high initial cost, poor reliability and large space requirements.
(d) both (a) and (b).
Answer: (d) both (a) and (b).
83. A gas turbine works on
(a) Carnot cycle,
(b) Brayton cycle.
(c) dual cycle.
(d) Rankine cycle.
(e) regenerative cycle.
Answer: (b) Brayton cycle.
84. Gas turbine is widely used in
(a) locomotives.
(b) automobiles.
(c) aircrafts.
(d) pumping stations.
Answer: (c) aircrafts.
85. Gas turbine power plants are not widely used
(a) as peak load plants.
(b) as standby power plants.
(c) as base load plants.
(d) in combination with steam power plants.
Answer: (c) as base load plants.
86. In comparison to steam power plants, the gas power plants have
(a) low initial cost but higher operating cost.
(b) high initial cost but low operating cost.
(c) both initial as well operating costs high.
(d) both initial as well as operating costs low.
Answer: (a) low initial cost but higher operating cost.
87. In which of the following places 70 MW gas turbine power plant being operated as base load plant ?
(a) Nangal (H.P.).
(b) Narnrup (Assam).
(c) Jharia (Bihar).
(d) Kokkata (W.B.).
Answer: (b) Narnrup (Assam).
88. The gas turbine power plants mainly use
(a) coal and peat.
(b) kerosine oil, diesel oil, residual oil.
(c) gas oil.
(d) natural gas and liquid petroleum fuels.
Answer: (d) natural gas and liquid petroleum fuels.
89. Compressor used in gas turbine is
(a) reciprocating compressor.
(b) screw compressor.
(c) multistage axial flow compressor.
(d) either (a) or (b).
Answer: (c) multistage axial flow compressor.
90. The blades of gas turbines are made of
(a) stainless steel.
(b) carbon steel.
(a) high alloy steel.
(d) high nickel alloy.
Answer: (d) high nickel alloy.
91. The pressure ratio in a gas turbine power plant is
(a) 5 to 6
(b) 9 to 12
(c) 2 to 3
Answer: (a) 5 to 6
92. The highest temperature ever used for gas turbine power plants is about
(a) 1,000°C
(b) 500°C
(c) 2,000°C
Answer: (a) 1,000°C
93. The heating value of gaseous fuels is about
(a) 300 kJ/litre.
(b) 100 kJ/litre.
(c) 30 kJ/litre.
(d) 10 kJ/litre.
Answer: (c) 30 kJ/litre.
94. Which of the following statements is not correct ?
(a) The efficiency of modern gas turbine power plants is more than 50%.
(b) One advanced feature of modern gas turbine power plants is higher firing temperature.
(c) The installed capacity of gas turbine power plants in India exceeds 20% of total installed generating capacity.
(d) The gas turbine power plants have the advantages of quick starting and capability of putting to share full load in few minutes.
Answer: (c) The installed capacity of gas turbine power plants in India exceeds 20% of total installed generating capacity.
95. Which of the following statements is correct ?
(a) In a gas turbine plant, the combustion takes place in the compressor.
(b) Aeroderivative turbines use clean fuel.
(c) Capital cost of a gas turbine power plant is higher than that of a steam power plant.
(d) Gas turbine power plants have the drawbacks of poor reliability and large space requirements.
Answer: (b) Aeroderivative turbines use clean fuel.
96. The compressor has to be started
(a) before starting of gas turbine.
(b) after starting of gas turbine.
(c) simultaneously with starting of gas turbine.
(d) at any time (i.e. before or after starting of gas turbine).
Answer: (a) before starting of gas turbine.
97. For starting gas turbine, its rotor is usually motored up to
(a) 10 percent of turbine rated speed.
(b) 25 percent of turbine rated speed.
(c) half of turbine rated speed.
(d) turbine rated speed.
Answer: (c) half of turbine rated speed.
98. In comparison to diesel engines the gas turbines have maximum combustion pressure
(a) less.
(b) same.
(c) more.
(d) unpredictable.
Answer: (a) less.
99. For the same cylinder size and speed which of the following engines will develop more power ?
(a) Petrol engine.
(b) Diesel engine.
(c) Supercharged engine.
(d) Gas engine.
Answer: (c) Supercharged engine.
100. Greater part of the power developed by the turbine is used in driving the compressor. It is around
(a) 75%
(b) 65%
(c) 45%
(d) 35%
Answer: (b) 65%