ch21

Question 1

current and the voltage of ac

Answer 1

I = I0 sinωt
V = V0 sinωt ////// Hence we can describe the angular frequency
of the current in rads−1 as ω where T = 2π/ω. The reciprocal of the period is the frequency f.
That is, f = 1/T and f = ω/2π. peak value of the current or voltage is I0 or V0

Question 2

peak value

Answer 2

The maximum value (amplitude) of the current or voltage from an alternating current supply.

Question 3

how to find frequency using cathode-ray oscilloscope (CRO)

Answer 3

T = Lx where L is the distance of one complete cycle and f=1/T

Question 4

the peak value V0

Answer 4

V0 = AQ The amplitude A of the trace is measured. If the y-gain setting is Q

Question 5

power in ac

Answer 5

P = I0^2Rsin^2ωt

Question 6

So the average power

<p>
</p>

Answer 6

<p> = 1/2I0^2R = 1/2V0^2/R

For a sinusoidal alternating current the mean power is half the maximum power.
</p>

Question 7

root-mean-square of i an v

Answer 7

Irms = <I^2> = I0/ 2 = 0.707I0
Vrms = <V^2> = V0/
2 = 0.707V0