AC Fundamentals - III

If the load impedance is 20 − j20, the power factor is _______

• 0.5

• 0

• 1

• 0.7071

If there is complex impedance in a circuit, part of energy is ____________ by reactive part and part of its energy is ____________ by the resistance.

• alternately stored and returned, alternately stored and returned

• alternately stored and returned, dissipated

• dissipated, alternately stored and returned

• dissipated, dissipated

If power factor = 1, then the current to the load is ______ with the voltage across it.

• out of phase

• in phase

• 90⁰ out of phase

• 45⁰ out of phase

A sinusoidal voltage v = 50sinωt is applied to a series RL circuit. The current in the circuit is given by I = 25sin (ωt-53⁰). Determine the apparent power (VA).

• 620

• 625

• 630

• 635

At resonant frequency, the voltage across capacitor is _______ the voltage across inductor.

• greater than

• less than

• greater than or equal to

• equal to

In series RLC circuit, the voltage across capacitor and inductor are ______ with each other.

• in phase

• 180⁰ out of phase

• 90⁰ out of phase

• 45⁰ out of phase

For the circuit shown in figure determine the capacitive reactance at resonance.

• 15

• 20

• 25

• 30

Determine the resonant frequency (kHz) for the circuit shown below.

• 2.25 kHz

• 22.5 kHz

• 225 kHz

• 2250 kHz

Find the resonant frequency in the ideal parallel LC circuit shown in the figure

• 7.118 Hz

• 71.18 Hz

• 711.8 Hz

• 7118 Hz

For the two magnetically coupled coils of Fig, the polarity of the mutual voltage is:

• Positive

• Negative