A coil with negligible resistance has 50V across it with 10 mA. The inductive reactance is_____________?

Related Mcqs:

1. 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

2. 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

3. 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

4. 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

5. 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

6. 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

7. In case all the flux from the current in coil 1 links with coil 2, the co-efficient of coupling will be____________?

   A. 2.0
   B. 1.0
   C. 0.5
   D. zero

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. For a purely inductive circuit which of the following is true ?

   A. Apparent power is zero
   B. Relative power is.zero
   C. Actual power of the circuit is zero
   D. Any capacitance even if present in the circuit will not be charged

10. Non inductive resistances are used in decreasing______________?

    A. Mutual inductance
    B. Self inductance
    C. Magnetic fields
    D. Heating effect