Two coils have inductances of 8 mH and 18 mH and a co-efficient of coupling of 0.5. If the two coils are connected in series aiding, the total inductance will be______________?

Related Mcqs:

1. 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

2. The self inductances of two coils are 8 mH and 18 mH. If the co-efficients of coupling is 0.5, the mutual inductance of the coils is______________?

   A. 4 mH
   B. 5 mH
   C. 6 mH
   D. 12 mH

3. Two 300 uH coils in series without mutual coupling have a total inductance of___________?

   A. 300 uH
   B. 600 uH
   C. 150 uH
   D. 75 uH

4. The co-efficient of coupling between two air core coils depends on____________?

   A. self-inductance of two coils only
   B. mutual inductance between two coils only
   C. mutual inductance and self inductance of two coils
   D. none of the above

5. Mutually inductance between two magnetically-coupled coils depends on____________?

   A. permeability of the core
   B. the number of their turns
   C. cross-sectional area of their common core
   D. all of the above

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. 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

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

   A. 64 A/s
   B. 32 A/s
   C. 16 A/s
   D. 4 A/s

9. 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

10. 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