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
Related Mcqs:
- 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 - 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 - If the coil is wound on an iron core the flux through it will_______________?
A. decrease
B. become zero
C. remain the same
D. increase - 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 - 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 - 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 - The self-inductance of a solenoid is increased when a soft iron core is inserted into it. This is because the soft iron core_______________?
A. Decreases the resistance of the solenoid
B. Reduces the effect of eddy current
C. Improves the flux linkage between the turns of the coil
D. Increases the mutual inductance between the solenoid and the core - 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 - If current in a conductor increases then according to Lenz’s law self-induced voltage will____________?
A. aid the increasing current
B. tend to decrease the amount of cur-rent
C. produce current opposite to the in-creasing current
D. aid the applied voltage - 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
