AC Basics

1. A current is said to be AC when it changes in ?
A- Both the magnitude and direction.


2.What is the most important advantage of using electrical energy in the form of AC?
A- Transformation is possible.


3. What will be the result when two sinusoids of same frequency and but different amplitudes and phase difference are added ?
A- Sinusoid of the same frequency.


4. When does a purely inductive circuit takes power from the AC mains ?
A- In the case when The applied voltage decreases but the current increases.


5. What is the Unit of Inductive Reactance ?
A- Ohm


6. A circuit component opposing a change in the Voltage of the circuit is ?
A- Capacitance.


7. What is the property of Power Factor for a Practical Inductor ?
A- Lagging


8. What is the Power Factor of a ordinary Electric Bulb ?
A- Sightly less than Unity Value.


9. Define Power Factor ?
A- Cosine of the phase angle.


10. At what level of Frequency in current , Skin Effect Takes place ?
A- High Frequencies.