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_____________?

Related Mcqs:

1. 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

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. Both the number of turns and the core length of an inductive coil are doubled. Its self-inductance will be_____________?

   A. unaffected
   B. doubled
   C. halved
   D. quadrupled

4. Two coils have self-inductances of 10 H and 2 H, the mutual inductance being zero. If the two coils are connected in series, the total inductance will be_____________?

   A. 6 H
   B. 8 H
   C. 12 H
   D. 24 H

5. 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

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. 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

8. The inductance of a coil will increase under all the following conditions except______________?

   A. when more length for the same number of turns is provided
   B. when the number of turns of the coil increase
   C. when more area for each turn is provided
   D. when permeability of the core increases

9. 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

10. 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