Basic Electrical Engineering MCQ_64_1(Electromagnetism)


Q.136 The electromagnetic torque of force developed in any physical system tends to____.
    A. increase the reluctance
    B. decrease the reluctance
    C. increase the magnetic stored energy
    D. increase the inductance
Ans.: B

Q.137 For microwave frequency, the core of transformer should made of ____.
    A. iron
    B. ferrite
    C. silicon carbide
    D. silicon
Ans.: B

Q.138 what will be the result, if a crack in the magnetic path of an inductor?
    A. inductance reduced
    B. inductance increase
    C. inductance will tends to zero
    D. inductance will tends to infinite
Ans.: A

Q.139 One Tesla is equal to __.
    A. 10-8 gauss
    B. 1010 gauss   
    C. 107 gauss
    D. 10-19 gauss  
Ans.: C
Q.140 A materials which is subjected to rapid reversal of magnetism should have__.
    A. low permeability and low hysteresis loss
    B. low permeability and low hysteresis loss
    C. high permeability and high hysteresis loss
    D. high permeability and low hysteresis loss
Ans.: D

Q.141 The magnetic material should have __ in order to minimize the loss due to hysteresis.
    A. high resistivity
    B. low hysteresis coefficient
    C. high hysteresis coefficient
    D. low reluctance
Ans.: B

Q.142 what is the unit of magnetic charge?
    A. Ampere-meter
    B. Ampere
    C. Coulombs
    D. meter per second
Ans.: A

Q.143 ____ will require the largest mmf.
    A. coil
    B. core
    C. resistance
    D. inductance
Ans.: D

Q.144 Lenz’s law is a consequence of the law of conservation of ___.
    A. charge
    B. Energy
    C. field
    D. all of the above
Ans.: B

Q.145 Magnetism in a substance is caused by which of the following?
    A. Spin and orbital motion of electrons
    B. Spin motion of electrons only
    C. Orbital motion of the electrons only
    D. due to high permeability
Ans.: C

Q.146 which of the following is not unit of inductance?
    A. Henry
    B. volt second per ampere
    C. coulomb per volt ampere
    D. none of the above
Ans.: C

Q.147 Which of the following is/ are correct
“A pure inductance when connected across 240 V, 50 Hz supply will consume 100 W”.
    A. inductance is made of thick wire
    B. inductance has silicon core
    C. pure inductor never consumes power
    D. none of the above
Ans.: C

Q.148 A DC voltage to an inductor is virtually a __.
    A. it consumes power with lagging P.F
    B. damage
    C. open circuited
    D. short circuited
Ans.: D

Q.149 The magnetic field at a distance r from a long wire carrying current is I is 0.8T. The magnetic field at a distance 2r is?
    A. 0.4 T
    B. 0.10 T
    C. 0.5 T
    D. 0.8 T
Ans.: A

Q.150 a long solenoid consists of 2000 turns and 0.2m long. What is the magnetizing force in the centre of the solenoid, if the current of 2 A is exciting?
    A. 4000 AT/m
    B. 6000 AT/m
    C. 5000 AT/m
    D. 1000 AT/m
Ans.: C

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