AC FUNDAMENTALS

When an alternating current passes through an ohmic resistance the electrical power converted into heat is

• Active Power

• Reactive power

• Apparent power

• All of the Above

The r.m.s. value of a sine wave is 100 A. Its peak value is

• 70.7 A

• 150 A

• 141 A

• 282.8 A

A small capacitance is added to a highly inductive circuit then,

• None

• The power factor will increase

• The power factor will decrease

• The power will be unity

In a pure inductive circuit

• The current is in phase with the voltage

• The current can lead or a lag by 90 degree

• The current leads the voltage by 90 degree

• The current lags behind the voltage by 90 degree

In a pure resistive circuit

• The current leads the voltage by 90 degree

• The current can lead or a lag by 90 degree

• The current is in phase with the voltage

• The current lags behind the voltage by 90 degree

Form factor for a sine wave is

• 1.414

• 0.707

• 1.111

• 0.637

A sine wave has a frequency of 50 Hz. Its angular frequency is _______

• 220

• 314.15

• 440

• 1382.30

The peak value of a sine wave is 200 V. Its average value is

• 127.4 V

• 141.4 V

• 282.8 V

• 200.0 V

Calculate the crest factor if the peak value of current is 10A and the rms value is 2A.

• 12A

• 20A

• 0.2A

• 5A

The peak value of a sine wave is 230 V. Its r.m.s value is

• 162.6 V

• 141.4 V

• 127.4 V

• 200.0 V