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Description :

Answer : In a synchronous motor, the armature current has large values for high and low excitation.

Description : A three-phase synchronous motor has a terminal voltage of 460 V and a terminal current of 120 A at a power factor of 0.95 lagging, synchronous reactance of 1.68 ohm and the field current is 47 A. The field to armature mutual inductance of the synchronous motor is _____________.      (a). 20mH   (b). 16mH   (c). 24mH   (d). 22mH

Answer : 22

Description : 1. If the current in the core decreases, what will the strength of the magnetic field be? 2. What is the commonly used unit for measuring the speed of data transmission? 3. The Govt. of India does not provide any direct financial assistance to which scheme? 4. Why is fog common around Newfoundland coast? 5. When Raja Wodeyar founded the kingdom of Mysore, who was the ruler of the Vijayanagar Empire? 6. Which tissue help in keeping the body warm? 7. Which State sends the maximum number of members to the Rajya Sabha? 8. Which gas has maximum colorific value? 9. Which is the capital of the Union Territory of Dadra and Nagar Haveli? 10. Who was the head of the Committee formed by the government to enquire into Jallianwala Bagh massacre? 11. Limba Ram is associated with which field? 12. Ms. Shilpa Singh Miss India Universe belongs to which city? 13. A molecule of glucose on complete oxidation yields howmany ATP molecules in case of aerobic respiration? 14. Kanchipuram is in which state? 15. Who was known as the ‘Liberator of the Press’ ? 16. By whom is the Chairman of Public Accounts Committee appointed? 17. A lighted candle gets extinguished when covered with a tumbler. Why? 18. With which India’s progress has been reasonably satisfactory in connection? 19. Which river flows between the Vindhya and Satpura ranges? 20. Which was a journal brought out by Abul Kalam Azad ?

Answer : Answer : 1. Decreases 2. Bits per second 3. Jeevan Sathi Yojana 4. Because warm and cold currents meet 5. Ranga II 6. Fatty tissue 7. Uttar Pradesh 8. Oil gas 9. Silvassa 10. Hunter 11. Sports ... 16. Speaker 17. Because of inadequate supply of air 18. Growth of GNP 19. Narmada 20. Al -Hilal

Description : Which of the following quantity maintains the same direction whether a D.C. machine runs as a generator or as a motor a. Induced e.m.f. b. Armature Current c. Field Current d. Supply Current  

Answer : Which of the following quantity maintains the same direction whether a D.C. machine runs as a generator or as a motor a. Induced e.m.f. b. Armature Current c. Field Current d. Supply Current  

Description :

A field excitation of 20 A in a certain alternator results in an armature current of 400 A in short circuit and a terminal voltage of 2000 V on open circuit. The magnitude of the internal voltage drop within the machine at a load current of 200 A is 

(A) 1 V (B) 10 V (C) 100 V (D) 1000 V

Answer : A field excitation of 20 A in a certain alternator results in an armature current of 400 A in short circuit and a terminal voltage of 2000 V on open circuit. The magnitude of the internal voltage drop within the machine at a load current of 200 A is 1000 V

Description : A 220 V dc machine has an armature resistance o f 1-ohm. If the full load current is 20A, the difference in the induced voltage when the machine is running as a motor, and as a generator is

Answer : A 220 V dc machine has an armature resistance o f 1-ohm. If the full load current is 20A, the difference in the induced voltage when the machine is running as a motor, and as a generator is 40 V.

Description :

Answer : When a conductor carries more current on the surface as compared to core, it is due to skin effect.

Description : A 50 kW dc shunt is loaded to draw rated armature current at any given speed. When driven  (i) at half the rated speed by armature voltage control and (ii) at 1.5 times the rated speed by field control, the respective output powers delivered by the motor are approximately. (A) 25 kW in (i) and 75 kW in (ii) (B) 25 kW in (i) and 50 kW in (ii) (C) 50 kW in (i) and 75 kW in (ii) (D) 50 kW in (i) and 50 kW in (ii)

Answer : A 50 kW dc shunt is loaded to draw rated armature current at any given speed. When driven  (i) at half the rated speed by armature voltage control and (ii) at 1.5 times the rated speed by field control, the respective output ... kW in (i) and 75 kW in (ii) (D) 50 kW in (i) and 50 kW in (ii)

Description : The supply both to field and armature circuits are disconnected simultaneously in a separately excited dc motor and it comes to a standstill in 5 sec. If the armature circuit of this motor is disconnected from supply with field circuit remaining energized, the motor would come to rest in (1) 5 sec (2) 7 sec (3) 4 sec (4) A very long time  

Answer : 5 sec only.standstill time doesn't depend upon field excitation

Description : In an AC. circuit, a low value of kVAR compared with kW indicates?

Answer : In an AC. circuit, a low value of kVAR compared with kW indicates high power factor.

Description : Why statistically is the unemployment rate low in India? Unemployment is calculated only from the age group 15 years to 59 years Unemployment survives only when an individual cannot find a job People are not interested in working outside the domestic area Choose the correct option. a) Only 3 b) 2 and 3 c) Only 2 d) All of the above

Answer : Answer- c

Description :

When running under no-load condition and with over excitation, armature current Ia drawn by a synchronous motor

Answer : When running under no-load condition and with over excitation, armature current Ia drawn by a synchronous motor Leads the applied voltage

Description : A 220 V shunt motor develops a torque of 54 N-m at armature current of 10 A. The torque produced when the armature current is 20 A, is?

Answer : Armature torque, Ta=PØZIa/2πA So Ta1/Ta2=Ia1/Ia2 Ta2=Ta1*Ia2/Ia1        =54*20/10         =108

Description :  A 4-pole 460V shunt motor has its armature wave connected with 888 conductors. The   useful flux per pole is 0.02 wb and the resistance of the armature circuit is 0.7Ω. if the  armature current is 40A. Calculate  (i) the speed (ii) the torque

Description : At low values of slip, the torque of an induction motor is   (a) directly proportional to the square of the slip. (b) inversely proportional to the square of the slip. (c) directly proportional to the slip. (d) inversely proportional to the slip. 

Description : With the help of neat diagrams,explain the following methods of speed control in DC series motor. i) Field diverter method. ii) Armature diverter method.

Answer : (i) Field diverter method: - Resistance connected in parallel with field winding -By adjusting this resistance current can by diverted from field winding -Thus field current decreases and the speed can be ... decreased, the flux must increase and hence speed is decreased than the rated speed.

Description :  If shunt generator delivers 100 A at 200 V, and the resistance of the shunt field and armature are 100 ohm and 0.01 ohm respectively, the generated e.m.f. will be : -  a) 212 V b) 205 V c) 210 V d) 201.02 V

Answer :  If shunt generator delivers 100 A at 200 V, and the resistance of the shunt field and armature are 100 ohm and 0.01 ohm respectively, the generated e.m.f. will be : - 201.02 V

Description : A DC shunt generator supplies 450 A at 230 V. The resistances of shunt field and armature are 50 Ω and 0.025 Ω respectively. What will be the armature voltage drop?  (A) 11.24 V (B) 22.7 V (C) 31.6 V (D) 38.4 V 

Description : A sine wave voltage is applied across an inductor. When the frequency of the voltage is decreased, the current decreases.

Answer : The question seems to be wrong. Increase in frequency would actually decrease the current through the Inductor. This happens because inductive reactance Xl is directly proportional to frequency. And if frequency increases the value of Xl would ... vice versa. Xl= 2*pi*f*L I=E/Z Z=sqrt(R^2+Xl^2)

Description : Which of the following are the parts of a DC generator that convert the AC in the armature to DC in the external circuit. Are these parts the: w) field poles x) slip rings and the brushes y) commutator and the brushes z) armature and the core

Answer : ANSWER: Y -- COMMUTATOR AND THE BRUSHES

Description : For a DC motor, what major component in addition to the field winding and the armature winding is necessary? w) a commutator x) a stator y) a battery z) a rotor

Answer : ANSWER: W -- A COMMUTATOR

Description :

Answer : A sinusoidal voltage of 5 Hz is applied to the field of a shunt generator. The armature voltage wave will be of 5 Hz.

Description : parallel operation of MOSFET can be done more easily as compared to thyristor. why?

Answer : Parallel operation of MOSFET can be done more easily as compared to thyristor because the resistance of MOSFET is increases with increase in temperature. MOSFET have the positive temperature coefficient. In ... the parallel operation of MOSFET can be done more easily as compared to the thyristor.

Description : The values of L and C for a low pass filter with cut off frequency of 2.5 KHz and operating with a terminated load resistance of 450 Ohm are given by  (a) 57.3 mH; 0.283 μF (b) 28.66 μH; 0.14 μF (c) 114.64 mH; 0.566 mF (d) 50.23 mH; 0.632 mF

Answer : The values of L and C for a low pass filter with cut off frequency of 2.5 KHz and operating with a terminated load resistance of 450 Ohm are given by 57.3 mH; 0.283 μF

Description : AC supply system compared to DC supply system has the advantage:

Answer : AC supply system compared to DC supply system has the advantage: low cost of switching

Description : If the load current and flux of a DC motor are held constant, and voltage applied across its armature is increased by 10%, its speed will:  (A) Decrease by 10%. (B) Remain unchanged. (C) Increase by 10%. (D) Increase by 20%. 

Description :

What will be the value of the current (in Ampere) in a 40 cm long solenoid in a free space, if it has 400 turns, 2 cm of diameter and produces a magnetic field of 4mT at its center

Description :

1. To meet the growing needs for coins in the country, where does the Government propose to set up another mint?

2. Which oil field of India is the oldest and still producing oil?

3. The first Muslim conquest of the Hindu Kingdoms of Deccan was effected by whose forces?

4. Since when has US been a member of the UN?

5. For pasteurisation of milk by Flash method, at which temperature is milk heated?

6. After howmuch time are the elections to Panchayats are to be held?

7. How are the orbits of planets around the Sun, or of satellites around the Earth,?

8. Buland Darwaza, built -by Akbar, is to commemorate the victory of which state?

9. A car is running on a road at a uniform speed of 60 km/hr. What is the net resultant force on the car?

10. Dog bite can cause rabies. Which other animals can also cause rabies?

11. For international payments, to which currency is the Indian currency linked?

12. What is the outermost layer of Sun called?

13. Where is the tomb of Babar?

14. Which chemical is used for preserving fruit juices?

15. How many High Courts in India have jurisdiction over more than one State (Union Territories not included)?

16. Which metal is found in ‘plaster of paris’ ?

17. The dry wind ‘Santa Ana’ blows in which country?

18. To which battle of the beginning of the British political sway over India can be traced?

19. Which animal which can tolerate more summer heat?

20. When does World Health Organization organise ‘World Aids Day’?


Answer : Answer : 1. Noida 2. Digboi 3. Alauddin Khilji 4. 1945 5. 100°C 6. Every five years 7. Circular and elliptic 8. Gujarat 9. Equal to zero 10. Bat 11. American Dollar 12. Corona 13. Kabul 14. Sodium benzoate 15. 3 16. Calcium 17. California 18. Plassey 19. Goat 20. 1st December

Description : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as  (1) synchronous motor (2) synchronous generator (3) asynchronous motor (4) asynchronous generator

Answer : In a synchronous machine, if the field flux axis ahead of the armature field axis in the direction of rotation, the machine is operating as synchronous generator 

Description : When hot liquid is poured into a thick glass tumbler, it cracks because glass : (1) is a bad conductor of heat so only inner surface expands (2) has high temperature coefficient of expansion (3) has a very low specific heat (4) has low temperature coefficient of expansion

Answer :  is a bad conductor of heat so only inner surface expands 

Description : The snow on the mountains does NOT melt all at once when it is heated by the sun because: (1) it becomes very hard (2) it reflects most of the heat from the sun (3) it has a low specific heat capacity (4) it has a high latent heat of fusion

Answer : it reflects most of the heat from the sun

Description : A dc voltmeter has a sensitivity of 1000 Ohm/V. When it measures half full scale in 100 V range, the current through the voltmeter is

Answer : A dc voltmeter has a sensitivity of 1000 Ohm/V. When it measures half full scale in 100 V range, the current through the voltmeter is 1 mA.

Description :

Answer : According to our application, we need low voltage and high voltage transformer.  High voltage tsansformer also called step up transformer. Low voltage transformer also called step down transformer ... tranformer used in consumer side or substation or special application like battery,etc...

Description : When excitation of synchronous motor is increased upto normal excitation from under excitation, armature current   (a) increases (b) decreases (c) remains constant (d) None of the above 

Description : 1. Balloons are filled with which gas? 2. Hitendra Desai was a noted figure in which field? 3. Which rural bank has been named after a river? 4. What happens when the water content in the atmosphere? 5. In which inscription are the achievements of Samudragupta described? 6. By which instrument the rate of growth of plant is measured? 7. In which ’ State, no tribe has been declared as ‘Scheduled’ by the President? 8. What is the The chemical part of the dye that absorbs light and produces colour called? 9. In the Semi-arid and Temperate grasslands, which are the most commonly found animals? 10. In which part was the Nagar style of architecture develop mostly? 11. Which Asian languages are UN official languages? 12. How many country are represented in International Monetary Fund (IMF)? 13. Translocation of carbohydrate nutrient usually occurs in which form? 14. Which tree is not a soft wood variety? 15. Which Sultan of Delhi has been described by the historians as the 'mixture of opposites' ? 16. When did Mr. Attlee, Prime Minister of England, announce tile transfer of power to the Indians? 17. Which when dissolved in HO gives hissing sound? 18. Unemployment occurs when workers move from one job to another job? 19. Which decaying vegetation produces organic acids which causes a breakdown of minerals? 20. Nicolo Conti, the traveller, who visited Vijayanagara kingdom in 1420 A.D., belongs to which country?

Answer : Answer : 1. Helium 2. Politics 3. Varada Grameen Bank 4. Decreases as temperature increases 5. Allahabad pillar inscription 6. Auxanometer 7. Haryana 8. A pigment 9. Sheep and goats10. ... Muhammad Tughluq 16. June, 1948 17. Limestone 18. Frictional unemployment 19. Chemical weathering 20. Italy

Description : What is the best data type definition for Oracle when a field is alphanumeric and has a length that can vary?  (1) VARCHAR2 (2) LONG (3) CHAR (4) NUMBER 

Description :

Answer : Because India uses 220-230volt  In USA there they uses 110volt

Description : Human lips have a reddish color because of the great concentration of tiny capillaries just below the skin. The blood in these capillaries is normally highly oxygenated and therefore quite red. This explains why the lips appear pale when a person is anemic or has lost a great deal of blood. It also explains why the lips turn blue in very cold weather. Cold causes the capillaries to constrict, and the blood loses oxygen and changes to a darker color.

Description : Why is the armature of DC generator laminated?

Answer : The armature of DC generator is laminated to reduce eddy current losses.

Description :  A single phase, 2000V alternator has armature resistance and reactance of 0.8 ohm and 4.94 ohm respectively. The voltage regulation of the alternator at 100A, 0.8 leading pf is (A) 7% (B) - 8.9% (C) - 6.3% (D) 0%

Description : What is the charge on each capacitor when a 150 V is applied across two capacitors with values 5 μF and 10 μF, connected in series? A) 500 μC B) 0.5 μC C) 0.5 C D) None of these

Answer : What is the charge on each capacitor when a 150 V is applied across two capacitors with values 5 μF and 10 μF, connected in series? A) 500 μC B) 0.5 μC C) 0.5 C D) None of these

Description : When three resistors with unequal values are connected in parallel, _______ A) The current across the resistors is the same  B) The voltage drop across the resistors is the same C) The voltage drops across the resistors is proportional to the resistance of each resistor D) None of these

Answer : When three resistors with unequal values are connected in parallel, The voltage drop across the resistors is the same

Description : Gamma rays are similar to X rays in which of the following ways? w) they have neither rest mass nor charge x) they can be bent in an electric field y) they originate within the nucleus z) they are of low energy

Answer : ANSWER: W -- HAVE NEITHER REST MASS NOR CHARGE

Description : Research in the field of juvenile delinquency would lead the teachers and parents to believe that Options: A) It is primarily a problem of foreigners in our society B) It is even worse in rural areas than in urban society C) It is disease of society limited to low economic areas D) It is a problem having many roots

Answer : D) It is a problem having many roots 

Description : A series R-L-C Circuit has a resonant frequency of 1000 Hz. If the values of R, L and C are doubled, the new resonant frequency is

Answer : A series R-L-C Circuit has a resonant frequency of 1000 Hz. If the values of R, L and C are doubled, the new resonant frequency is 500 Hz

Description : If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: (1) 50% of the previous value (2) 25% of the previous value (3) 150% of the previous value (4) 125% of the previous value

Answer : If the current in the armature of do series motor is reduced to 5%, the torque of the motor will become: 25% of the previous value

Description : The torque, in a_______ is proportional to the square of the armature current. (A) DC shunt motor (C) 2 -phase servomotor (B) stepper motor (D) DC series motor

Answer : The torque, in a DC series motor is proportional to the square of the armature current. 

Description :

Answer : In D.C. generators, current to the external circuit from armature is given through commutator commutator.

Description :

Answer : The current drawn by the armature of D.C. motor is directly proportional to the torque required.

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