Magnetism & Electromagnetism Electrical Engineering MCQ - Set 03 - ObjectiveBooks

Magnetism & Electromagnetism Electrical Engineering MCQ - Set 03

Practice Test: Question Set - 03

1. Main causes of noisy solenoid are
    (A) Strong tendency of fan out of laminations at the end caused by repulsion among magnetic lines of force
    (B) Uneven bearing surface, caused by dirt or uneven wear between moving and stationary parts
    (C) Both of above
    (D) None of the above

2. A basic one-loop dc generator is rotated at 90 rev/s. How many times each second does the dc output voltage peak (reach maximum)?
    (A) 90
    (B) 180
    (C) 270
    (D) 360

3. Paramagnetic materials have relative permeability
    (A) Slightly less than unity
    (B) Equal to unity
    (C) Slightly more than unity
    (D) Equal to that ferromagnetic mate rails

4. When the speed at which a conductor is moved through a magnetic field is increased, the induced voltage
    (A) Increases
    (B) Decreases
    (C) Remain constant
    (D) Reaches zero

5. A relay is an electromagnetically controlled mechanical device in which electrical contacts are opened or closed by a magnetizing current.
    (A) True
    (B) False

6. The magnetism left in the iron after exciting field has been removed is known as
    (A) Permeance
    (B) Residual magnetism
    (C) Susceptance
    (D) Reluctance

7. When the north poles of two bar magnets are brought close together, there will be
    (A) No force
    (B) A downward force
    (C) A force of attraction
    (D) A force of repulsion

8. Susceptibility is positive for
    (A) Nonmagnetic substances
    (B) Diamagnetic substances
    (C) Ferromagnetic substances
    (D) None of the above

9. If a loop in a basic dc generator suddenly begins rotating at a faster speed, the induced voltage
    (A) Remains unchanged
    (B) Reverses polarity
    (C) Increases
    (D) Decreases

10. The most effective and quickest may of making a magnet from soft iron is by
    (A) Placing it inside a coil carrying current
    (B) Induction
    (C) The use of permanent magnet
    (D) Rubbing with another magnet

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