INDUCTORS QUIZ

Two inductors, L1 and L2, are in parallel. L1 has a value of 25 H and L2 a value of 50 H. The parallel combination is in series with L3, a 20 H coil. The entire combination is across an ac source of 60 Vrms at 300 kHz. The total rms current is

87 mA

337 mA

87 A

870 mA

TRUE ANSWER : ?
YOUR ANSWER : ?

An inductor and a resistor are in series with a sine wave voltage source. The frequency is set so that the inductive reactance is equal to the resistance. If the frequency is increased, then

VL > VR

VL < VR

VR ≥ VL

VL = VR

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YOUR ANSWER : ?

The inductance of an iron-core coil decreases if

the length of the coil decreases

None of these

the iron core is removed

the number of turns is decreased

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A 240 H inductor is equivalent to a

240 H inductor

0.240 mH inductor

240 mH inductor

0.000240 mH inductor

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A switch, a 220 Ω resistor, and a 60 mH inductor are in series across a 20 V battery. What is the current through the inductor two time constants after the switch is closed?

57 mA

91 mA

78 mA

400 mA

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A 2 mH, a 3.3 mH, and a 0.2 mH inductor are connected in series. The total inductance is

less than 5.5 mH

less than 0.2 mH

5.5 mH

55 mH

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An inductance of 0.08 μH is larger than

0.000008 H

0.000000008 H

0.0000008 H

0.00008 mH

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When the current through an inductor is cut in half, the amount of energy stored in the electromagnetic field

does not change

is quartered

quadruples

doubles

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An inductance of 0.43 mH is smaller than

430 μH

43 μH

0.00043 H

0.05 H

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The current through a 120 mH coil is changing at a rate of 150 mA/s. The voltage induced across the coil is

18 mV

180 mV

1.25 mV

1.8 mV

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