A.C. current

Question 1

sinusoidal alternating current

Answer 1

Current that has positive and negative signs, implies that charges have to move to and fro in simple harmonic motion

Question 2

Transformer

Answer 2

increasing/decreasing the potential difference of an alternating supply using principle of electromagnetic induction

Question 3

What is rectification

Answer 3

A process of converting an alternating current to a direct current using a diode or multiple diodes

For full wave rectification, four diodes needed

Question 4

Voltage is step up near the power plant

Answer 4

The same power delivered at higher transmission voltage would result in a lower
transmission current.
Lower current results in lower power loss/dissipated in the power cables.

Question 5

Use of AC rather than dc

Answer 5

Alternating voltage can set up a changing magnetic flux linkage in a transformer
which can be used to step the transmission voltage up or down.

Question 6

high voltage required

Answer 6

For a CONSTANT power delivered, using a high voltage implies that the current I is low.

Since the power loss in the transmission cables of resistance R is proportional to the square of the current, power loss during the transmission will be minimized

Question 7

Root Mean Square Current

Answer 7

The Root Mean Square Current of an alternating current is the

1) steady direct current that will
2) dissipate heat at the
3) same rate as the alternating current
4) in a given resistor

Question 8

Mean power of half-wave rectification

Answer 8

Mean Power=1/4Max power

Question 9

RMS current in an half wave rectified system

Answer 9

0.5 Max Current

Question 10

Is mean power dependent on frequency?

Answer 10

No, mean power is independent of the frequency of the a.c.

Question 11

Period of Instantaneous Power vs Period of Sinusoidal A.C current

Answer 11

Period of Instantaneous Power is half of that of the current

And voltage