MCQs on AC generator for NEET 2020

AC generator is also known as an alternator. It is a device that converts mechanical energy into electrical energy. The electrical energy generated is in the form of an alternating current. The mechanical energy is usually supplied by combustion engines, gas turbines and steam turbines. AC generators work on the principle of Faraday’s law of electromagnetic induction.

Q1: An alternator is an electromechanical ac generator.

  1. True
  2. False

Answer: (B) False

Q2: In A.C generator increasing the no. of turns in the coil

  1. Decreases the Electromotive force (EMF)
  2. Electromotive force (EMF) remains the same
  3. Increases the Electromotive force (EMF)
  4. Electromotive force (EMF) becomes zero

Answer: (c) Increases the Electromotive force (EMF)

Q3: The Electromotive force (EMF) developed by the generator depends upon

  1. Area of rotating wire
  2. length of rotating wire
  3. Radius of wire
  4. size of magnet

Answer: (b) length of rotating wire

Q4: The metal detectors installed at airports and other places for security purpose are based on the principle of

  1. potential difference
  2. electromagnetic difference
  3. electromagnetic induction
  4. potential energy

Answer: (c) electromagnetic induction

Q5: If the coil is placed perpendicular to field lines then the number of lines passing through the coil is

  1. Minimum
  2. maximum
  3. zero
  4. maybe maximum or minimum

Answer: (b) maximum

Q6: In alternative current generator, AC current reverses its direction

  1. 10 times per second
  2. 20 times per second
  3. 60 times per second
  4. 50 times per second

Answer: (d) 50 times per second

Q7: Name two main parts of an AC generator

  1. Stator
  2. Rotor
  3. Both 1 and 2
  4. None of these

Answer: (c) Both 1 and 2

Q8: AC generator converts

  1. Mechanical energy to electrical energy
  2. Electrical energy to mechanical energy
  3. Heat energy to mechanical energy

Answer: (a) Mechanical energy to electrical energy

Q9: What replacement is required to convert an AC generator to DC generator?

  1. Concave magnets with horseshoe magnets
  2. Armature with coil
  3. Slip rings with split rings
  4. None of the above

Answer: Slip rings with split rings

Q10: The direction of induced emf or current is indicated by

  1. Fleming’s left-hand rule
  2. Fleming’s right-hand rule
  3. Faraday’s law of electromagnetic induction
  4. None of these

Answer: (b) Fleming’s right-hand rule

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