CBSE Class 12 Physics Electromagnetic Induction Quiz 1

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

A Zero B 1 C slightly more than 1 D infinite

2. 1 henry is equal to :

A \(\frac{weber}{ampere}\) B \(\frac{weber}{Volt}\) C weber ampere D None of these

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

A zero B small but not zero C infinite D large but not infinite

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

A The induced emf is produced only when magnetic flux decreases B The induced emf opposes the change in the magnetic flux C The induced emf is opposite to the direction of the flux D 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:

A 1840 times that on e^- B less than that of e^- C same as that of e^- D slightly more than that of e^-

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

A \(\frac{Volt second}{ampere}\) B \(\frac{Volt second^2}{Coulomb}\) C \(\frac{Volt^2 second}{Coulomb}\) D \(\frac{Jole second}{Coulomb^2}\)

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:

A 11% B 50% C 80% D 90%

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

A f ∝ N B f ∝ N^-1 C f ∝ N² D f ∝ N^-2

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

A ∅ ∝ s B ∅ ∝ s² C ∅ ∝ s^1/2 D ∅ ∝ 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:

A \(\frac{l}{∅}\) B \(\frac{∅}{l}\) C ∅l D None of these