Answers to AC Homework

  Frequency and Period 

 1.a.	f = 50Hz
   b.	f = 20Hz
   c.	f = 33.33Hz
   d.	f = 500x103Hz

 2.a.	T = 0.01s
   b.	T = 0.005s
   c.	T = 1x10-6s
   d. 	T = 4s

  Peak and RMS Voltage/Current

 3.	VRMS = 8.49V
 4.	Vpeak = 7.07V
 5.	IRMS = 2.83A
 6.	Ipeak = 7.07A
 7.	B
 8.	None of the given options.
	Vdc = VRMS = Vpeak/SQRT2 = 10/SQRT2
 9.	C

  Oscilloscope Patterns

10.	D
11.a.	Vpeak = 15V
   b.	VRMS =  15/SQRT2 = 10.61V
   c.	Period(T) = 5ms
      =>f = 1/T =200Hz	
   d.	
	
12.	B
	[T = 1/f =0.02s = 20ms
	4cm = 20ms
      =>1cm = 5ms] 

13.	C
	T = 1/f =0.02s = 20ms
	8 divisions x time per division = 20ms
	time per division = [20/1000]/8
        time per division =  20/8000 = 1/400 seconds

14.	C   	(1999 PI  Q16)
	

  RMS and DC Equivalence

15.	Idc = 0.57A
16.	VRMS = 7.07V =>Vpeak = 10V
	Amplitude = 5 divisions (at 2V/div)
17.	P = 24W
18.	P = 6.4W
19.	E = 33.75J
20.	B	(1994 PI  Q18)

  Current and Frequency

21.	A	(1997 PI  Q19)
22.	E	(1999 PI  Q17)