CBSE  /  Class 12  /  Physics  /  Electromagnetic Induction

  • 1. 
    In a uniform magnetic field B, a wire in the form of a semicircle of radius r rotated about the diameter of the circle with angular frequency ‘ω’. The axis of rotation is perpendicular to the field. If the total resistance of the circuit is R the mean power generated per period of rotation is :

  • \(\frac{Bπr^2ω}{2R}\)
  • \(\frac{(Bπr^2ω)^2}{8R}\)
  • \(\frac{(Bπrω)^2}{2R}\)
  • \(\frac{(Bπrω^2)^2}{8R}\)

  • 2. 
    The role of inductance is equivalent to:

  • inertia
  • force
  • energy
  • momentum

  • 3. 
    A metal conductor of length 1 m rotates vertically about one of its ends at angular velocity 5 rad s-1. If the horizontal component of earth's magnetism is 2 × 10-5 T, then e.m.f. developed between the two ends of the conductor is:

  • 5 µV
  • 50 µV
  • 5 mV
  • 50 mV

  • 4. 
    coil of L = 8.4 mH and R = 6 Ω is connected to a 12 V battery. The current in the coil is 1.0 A at approx'time of:

  • 500 s
  • 20 s
  • 35 ms
  • 1 ms

  • 5. 
    If I current is flowing inductance L, then the dimension of \(\frac{3}{2}\) LI² is equivalent to:

  • charge
  • force
  • momentum
  • energy

  • 6. 
    The phase difference between the flux linkage and the emf in a rotating coil in a uniform magnetic field is:

  • zero
  • \(\frac{π}{2}\)
  • \(\frac{π}{4}\)
  • π

  • 7. 
    A choke is used as a resistance in :

  • dc circuits
  • ac circuits
  • both ac and dc circuits
  • neither (a) nor (b)

  • 8. 
    The SI unit of magnetic flux is:

  • T
  • Tn-2
  • Wb
  • Wb m-2

  • 9. 
    For purely capacitive circuits, power factor is:

  • 0
  • -1
  • 1
  • infinity

  • 10. 
    The magnetic flux linked with a coil is inversely proportional to the?

  • magnetic field
  • area of cross section
  • number of turns
  • none of these
Report Question
warning
Practice More On Electromagnetic Induction
Quiz 1 Quiz 2 Quiz 3
access_time
  Time