An e.m.f. of 16 volts is induced in a coil of inductance 4H. The rate of change of current must be______________?

Related Mcqs:

1. The self-inductance of the coil may be defined as equal to the e.m.f. induced in volts when the current in the circuit changes at the rate of unit Weber turns

   A. Yes
   B. No

2. In an iron cored coil the iron core is removed so that the coil becomes an air cored coil. The inductance of the coil will_____________?

   A. increase
   B. decrease
   C. remain the same
   D. initially increase and then decrease

3. Current changing from 8 A to 12 A in one second induced 20 volts in a coil. The value of inductance is___________?

   A. 5 mH
   B. 10 mH
   C. 5 H
   D. 10 H

4. The core of a coil has a length of 200 mm. The inductance of coil is 6 mH. If the core length is doubled, all other quantities, remaining the same, the inductance will be_____________?

   A. 3 mH
   B. 12 mH
   C. 24mH
   D. 48mH

5. 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

6. A 200 turn coil has an inductance of 12 mH. If the number of turns is increased to 400 turns, all other quantities (area, length etc.) remaining the same, the inductance will be___________?

   A. 6 mH
   B. 14 mH
   C. 24 mH
   D. 48 mH

7. The property of coil by which a counter e.m.f. is induced in it when the current through the coil changes is known as__________?

   A. self-inductance
   B. mutual inductance
   C. series aiding inductance
   D. capacitance

8. A coil is wound on iron core which carries current I. The self-induced voltage in the coil is not affected by________________?

   A. variation in coil current
   B. variation in voltage to the coil
   C. change of number of turns of coil
   D. the resistance of magnetic path

9. A small coil lies inside a large coil. The two coils are horizontal concentric and carry currents in opposite directions. The large coil will experience______________?

   A. A torque about horizontal axis
   B. A torque about vertical axis
   C. An upward force along the axis
   D. No resultant force

10. A coil induces 350 mV when the current changes at the rate of 1 A/s. The value of inductance is___________?

    A. 3500 mH
    B. 350 mH
    C. 250 mH
    D. 150 mH