Energy stored in a magnetic field is given by______________?

Related Mcqs:

1. Lagging of changes in the magnetization of a substance behind changes in the magnetic field as the magnetic field is varied is known as magnetic_____________?

   A. Retaintivity
   B. Permeability
   C. Flux
   D. Hysteresis

2. An electric current induced within the body of a conductor when that conductor either moves through a non uniform magnetic field or in a region where there is a change in magnetic flux is called_____________?

   A. Induced current
   B. Eddy current
   C. Back emf
   D. None of the above

3. Current produced by moving the loop of wire across a magnetic field is called_____________?

   A. A.C current
   B. D.C current
   C. induced current
   D. mean square current

4. Which of the following works on torque on the current carrying conductor placed in magnetic field ?

   A. galvanometer
   B. ammeter
   C. voltmeter
   D. all of the above

5. The emf induced in a conductor of unit length moving with unit velocity at right angles to a magnetic field is equal to_____________?

   A. Magnetic flux density
   B. Torque
   C. Mutual induction
   D. Motional emf

6. A coil of wire is arranged with its plane perpendicular to a uniform magnetic field o flux density B. when the radius of the coil increases from r1 to r2 in time Δt then what is the emf induced in the coil ?

   A. ωB/r22-r12/Δt
   B. ωB(r2-r1)2/Δt
   C. ωB(r22-r12)/Δt
   D. ωB(r22+r12)/Δt

7. An aeroplane of wingspan 10m flies from the equator towards the North Pole. The wings are perpendicular to the vertical component of the earths magnetic field (B = 4×10-5T). At maximum speed an emf of 96mV is induced across the wing tips. The maximum speed of the aeroplane is____________?

   A. 150msec-1
   B. 384msec-1
   C. 38.4msec-1
   D. 200msec-1

8. A metal rod of 25 cm length is moving at a speed of 0.5/sec in direction perpendicular to 0.25T magnetic field. Emf produced in the rod is_____________?

   A. 0 volt
   B. 3.125 volt
   C. 31.25 volt
   D. 0.03125 volt

9. A conductor carries 125 amperes of current under 60° to a magnetic field of 1.1 tesla. The force on the conductor will be nearly______________?

   A. 50 N
   B. 120 N
   C. 240 N
   D. 480 N

10. A conductor 2 meters long moves at right angles to a magnetic field of flux density 1 tesla with a velocity of 12.5 m/s. The induced e.m.f. in the conductor will be____________?

    A. 10 V
    B. 15 V
    C. 25V
    D. 50V