Electronics and Electrical Engineering 5

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Mechanical Engineering MCQ Question Papers: DRDO, ISRO, Interview

Subject: Electronics and Electrical Engineering 5

Part 5: List for questions and answers of Electronics and Electrical Engineering

Q1. The following magnet is used in large machines to create magnetic flux
a) Permanent magnet
b) Electro magnet
c) Temporary magnet
d) Any of the above

Q2. The special device which converts AC into DC and vice versa is known as
a) Armature
b) Slip rings
c) Split rings
d) Field magnets

Q3. The following is (are) the part(s) of a field magnet
a) Yoke
b) Pole cores
c) Pole shoes
d) All of the above

Q4. Function of _____ is to collect current from the commutator and supply it to the external load
a) Field magnet
b) Armature
c) Brushes
d) Yoke

Q5. The brushes are ____ in shape
a) Triangular
b) Rectangular
c) Cylindrical
d) Square

Q6. For larger machines
a) Ball bearings are used at both driving and non driving ends
b) Ball bearings are used at driving end and roller bearings are used at non driving end
c) Roller bearings are used at driving end and ball bearings are used at non driving end
d) Roller bearings are used at both driving and non driving ends

Q7. The following is (are) keyed to the shaft
a) Armature core
b) Commutator
c) Cooling fan
d) All of the above

Q8. Which of the following generators have two field windings?
a) Series wound generator
b) Shunt wound generator
c) Compound wound generator
d) All of the above

Q9. A motor converts
a) Mechanical energy into electrical energy
b) Chemical energy into electrical energy
c) Electrical energy into Mechanical energy
d) Electrical energy into chemical energy

Q10. To produce dynamically induced emf, the following is (are) necessary
a) A magnetic field
b) A conductor
c) Motion of conductor with respect to the field
d) All of the above

Q11. Which of the following is also called ‘motor rule’?
a) Fleming’s right hand rule
b) Fleming’s left hand rule
c) Fleming’s Thumb rule
d) All of the above

Q12. Shaft torque equals to
a) Net torque
b) Friction torque
c) Net torque + Friction torque + Torque lost
d) Net torque – (Friction torque + Torque lost)

Q13. Iron or magnetic losses are also called
a) Core losses
b) Field losses
c) Copper losses
d) Armature losses

Q14. The mechanical losses are about _____ % of full load losses
a) 0 to 10
b) 10 to 20
c) 20 to 30
d) 30 to 40

Q15. If field current is decreased in shunt dc motor, the speed of the motor
a) Remains same
b) Increases
c) Decreases
d) None of the above

Q16. What is the mechanical power developed by a DC series motor is maximum?
a) Back emf is equal to half the applied voltage
b) Back emf is equal to applied voltage
c) Back emf is equal to zero
d) None of above

Q17. In Ward-Leonard system, the lower limit of the speed imposed by
a) Field resistance
b) Armature resistance
c) Residual magnetism of the generator
d) None of above

Q18. Ward-Leonard control is basically a _____control method
a) Field control
b) Armature resistance control
c) Armature voltage control
d) Field diverter control

Q19. For very sensitive and wide speed control, the preferable control method is
a) Armature control
b) Ward-Leonard control
c) Multiple voltage control
d) Field control

Q20. Commutator pitches of duplex and simplex lap windings are respectively
a) 4 and 2
b) 2 and 1
c) 4 ang 1
d) 2 and 2

Part 5: List for questions and answers of Building Technology and Materials

Q1. Answer: b

Q2. Answer: c

Q3. Answer: d

Q4. Answer: c

Q5. Answer: b

Q6. Answer: c

Q7. Answer: d

Q8. Answer: c

Q9. Answer: c

Q10. Answer: c

Q11. Answer: b

Q12. Answer: d

Q13. Answer: a

Q14. Answer: b

Q15. Answer: b

Q16. Answer: a

Q17. Answer: c

Q18. Answer: c

Q19. Answer: b

Q20. Answer: b