# The efficiency of modern steam turbines is about

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The efficiency of modern steam turbines is about (1) 50% (2) 85% (3) 75% (4) 90%

## Related questions

Overall thermal efficiency of a steam power station in India is in the range: A) 18-24 percent B) 30-40 percent C) 44-62 percent D) 68-79 percent

The rankine cycle efficiency of steam power plant is  (1) 60-80% (3) 30-45% (2) 45-80% (4) 20-30%

If modulation index is 0.6, maximum power efficiency (in %) of AM is about  A) 60 B) 30 C) 20 D) 10

The transfer of energy for reaction turbines is based on _______ A) Newton’s first law B) Newton’s second law C) Newton’s third law D) All the above

The steam input in to a turbogenerator connected to infinite bus is increased. Which of the events will take place? (a) The generator will feed more leading KVAR to bus bar and power angle will not change (b) The generator will feed more real power to bus bar and power angle will increase (c) The generator will feed more power to bus bar and power angle will decrease (d) The generator will feed more lagging KVAR to bus bar and power angle will not change

Typical value of SCR for modern turbo alternator is (1) 1 (2) 1.2 (3) 0.5 (4) 1.5

What is the purpose of the turbines in coal fired power plants?

The dielectric strength of impregnated papers is about   (a) 20 kV/mm (b) 30 kV/mm (c) 15 kV/mm (d) 5 kV/mm

It is desired to illuminate a drawing hall with an average illumination of about 250 lux. The area of hall is 30 m × 20 m. The lamps are to be fitted at 5 m height. Find the number and size of incandescent lamps required for an efficiency of 12 lumen/watt. Utilization factor = 0.4 and maintenance factor = 0.85.   (a) 40 and 1000 W (b) 20 and 500 W (c) 60 and 1000 W (d) None of the above

At atmospheric pressure, the dielectric strength of SF6 is about   (a) 2.5 times of air (b) 2.5 times of oil (c) 2.5 times of vacuum (d) None of the above

Which of the statements about the force between two charge is true?  (1) Unlike charges repel each other (2) Like charges attract each other (3) No force exists between two unlike charges (4) A force of repulsion exists between two like charges

The usual value of slip of a 3Φ induction motor at full load is about:  (A) 0.05 (B) 0.1 (C) 0.3 (D) 0.8

The hot resistance of a tungsten lamp is about 10 times the cold resistance. Accordingly, cold resistance of a 100 W, 200 V lamp will be

The DFD is  (1) modern version of flowchart (2) mainly used at system specification stage (3) primary output of the system design phase (4) all of these

The insulation of modern EHV lines is designed based on?

When a source is delivering maximum power to a load, the efficiency of the circuit is always (a) 50% (b) 75% (c) 100% (d) Depends on the circuit parameters

The overall efficiency of thermal station is (1) 40% (2) Less than 40% (3) More than 40% (4) 50%

The efficiency of a transformer at full load 0.8 p.f lagging is 90%. Its efficiency at full load 0.8 p.f leading will be (1) Less than 90% (2) More than 90% (3) 90% (4) None of these

The all-day efficiency of a transformer is the ratio of (1) kWh output and kWh input per day (2) kWh output and kWh input in a day (3) output power and input power (4) input power and output power

A transformer has maximum efficiency at 3/4 full load. The ratio of its iron losses and full load copper loss is : -  a) 16/9 b) 4 / 3 c) 3/4 d) 9 /16

State the types of wind turbines.

Kaplan turbines are used whenever the water head is (a) low (b) high (c) medium (d) (b) and (c)

In steam locomotive, electric power is provided through   (a) Battery system (b) Diesel engine generator (c) Overhead wire (d) Small turbo generator

When two alternators A and B are operating in parallel, the increase in steam supply to alternator A will cause the active power output of (1) Alternator A to be decreased and alternator B to be increased (2) Alternators A and B is not affected (3) Alternators A and B is increased (4) Alternator A to be increased and alternator B to be decreased

In river crossing, hilly terrain, modern HV lines have span more than (a) 50 m (c) 500 m (b) 100 m (d) 800 m

A power supply produces a 0.6 W output with an input of 0.7 W. Its percentage of efficiency is: A. 8.57% B. 42.85% C. 4.28% D. 85.7%

A 150 kW electric motor has an efficiency of 92 %, when it operates at full load. Calculate the losses in the machine.  (A) 92 kW (B) 150 kW (C) 163 kW (D) 13 kW

The efficiency of a solar cell can be expected in the range : (A) 10 to 15 percent (B) 25 to 30 percent (C) 45 to 60 percent (D) 70 to 80 percent

A diesel power station spends 0.25 kg/kWh fuel. If the calorific value is 10,000 kcal/kg then overall efficiency of the power station will be   (a) 25% (b) 30% (c) 34.4% (d) 100%

Which statement out of the following statements about ‘corona’ is incorrect? A) Corona gives rise to radio interference B) Corona results in loss of power in transmission C) Corona discharge can be observed as red luminescence D) Corona is always accompanied by a hissing voice

The best indication about the state of charge on a lead acid battery is given by_______.

The algebraic sum of moments of the forces forming couple about any point in their plane is?

Transient stability can be improved by using governors attached to the turbines, should be (a) fast acting (b) slow acting (c) no function of governors in improving stability (d) nothing can be said