11. Inductance/inductor.- Parte 66

Two inductive coils are placed in close proximity with each other at 90 degrees. The number of flux linkages is. 0. maximum negative. maximum positive.

What is the mutual inductance if two coils of 10mH and 500mH have 90% of the flux transferred from one to the other?. 459mH. 4.5mH. 63mH.

An inductor has 1,000 turns of wire and a cross sectional area of 0.001m2. If the core has a permeability of 0.000,001 and the coil is 0.1m. What is the value of the inductor?. 100microH. 100mH. 10mH.

Three inductors 10 mH, 5 mH and 20 mH are connected in parallel. What is the total inductance?. Without knowing the coupling factor the total inductance cannot be found. 2.86mH. 35mH.

If the current reaches a maximum through an inductor of 2A in 15 seconds, what is the current after 3 seconds?. 1.26A. 0.63A. 1A.

The time constant of an inductor is. L/R. L2 /R. LR.

If the rate of change of current is halved, mutual inductance will. stay the same. halve. double.

Why are the iron cores of most induction coils laminated?. To reduce the effects of eddy currents. To reduce the core reluctance. To increase the core permeability.

When more than two inductors of different inductance are connected in parallel in a circuit, the total inductance is. equal to the sum of the individual inductance. equal to the inductance of the highest rated inductor. less than the inductance of the lowest rated inductor.

The time constant in an inductive circuit is the time required for the current to reach. 70.7% of maximum value. 63.2% of maximum value. 63.7% of maximum value.

An AC inductive circuit has an inductance 0f 10 mH and a frequency input of 1000Hz. The opposition to current flow is approximately. 63 ohms. 63,000 ohms. 630 ohms.

Rotating coil B through 90° will. increase the EMF induced into B. increase the EMF induced into A. decrease the EMF induced into B.

An inductor of resistance 5 kΩ and inductance 2mH is connected to a DC circuit. The time constant is. 400 ns. 10 seconds. 40 ms.

When switching off the supply, the back EMF in a collapsing field in an inductor. can be multiple times bigger than forward EMF. never exceeds forward EMF. is equal to forward EMF.

An induced current in a coil. opposes the EMF producing it. does not affect the EMF producing it. aids the EMF producing it.

1 Volt is produced when a current of 1 Amp per second is varied in a coil'. This is a definition of. 1 Ampere per metre. 1 Henry. 1 Coulomb per second.

Two inductor coils in very close proximity; if one of the coils is rotated 90 degrees slowly away from the other the mutual inductance. decreases. remains the same. increases.

An inductor is said to be saturated when. the current is at a maximum. the current through it is zero. it will no longer accept lines of flux.