CBSE  /  Class 12  /  Physics  /  Electromagnetic Induction

  • 1. 
    The coupling co-efficient of the perfectly coupled coils is:

  • Zero
  • 1
  • slightly more than 1
  • infinite

  • 2. 
    1 henry is equal to :

  • \(\frac{weber}{ampere}\)
  • \(\frac{weber}{Volt}\)
  • weber ampere
  • None of these

  • 3. 
    The magnetic field is parallel to a surface, then the magnetic flux through the surface is :

  • zero
  • small but not zero
  • infinite
  • large but not infinite

  • 4. 
    In the expression e = -\(\frac{d∅}{dt}\), the -ve sign signifies:

  • The induced emf is produced only when magnetic flux decreases
  • The induced emf opposes the change in the magnetic flux
  • The induced emf is opposite to the direction of the flux
  • None of these

  • 5. 
    An e- and a p- are moving parallel to each other in a magnetic field. The magnetic force acting on the p+ is:

  • 1840 times that on e-
  • less than that of e-
  • same as that of e-
  • slightly more than that of e-

  • 6. 
    Which of the following is not equal to a henry?

  • \(\frac{Volt second}{ampere}\)
  • \(\frac{Volt second^2}{Coulomb}\)
  • \(\frac{Volt^2 second}{Coulomb}\)
  • \(\frac{Jole second}{Coulomb^2}\)

  • 7. 
    A transformer is used to light 100 W and 110 V lamp from a 220 V mains. If the main current is 0.5 A. Then the efficiency of the transformer is:

  • 11%
  • 50%
  • 80%
  • 90%

  • 8. 
    The magnetic flux (∅) linked with a coil is related to the number of turns (N) ofthe coil as:

  • f ∝ N
  • f ∝ N-1
  • f ∝ N2
  • f ∝ N-2

  • 9. 
    The magnetic flux (∅) lined with a coil is related to its area (s) as:

  • ∅ ∝ s
  • ∅ ∝ s²
  • ∅ ∝ s1/2
  • ∅ ∝ s-1/2

  • 10. 
    If the magnetic flux linked with a coil through which a current off ampere is set up is ∅, then the coefficient of self-inductance of the coil is:

  • \(\frac{l}{∅}\)
  • \(\frac{∅}{l}\)
  • ∅l
  • None of these
Report Question
warning
Practice More On Electromagnetic Induction
Quiz 1 Quiz 2 Quiz 3
access_time
  Time