|QUIZ 22 CH.22|
SELECTED DISCUSSIONS TO exercises/problems
YOU ARE RESPONSIBLE FOR ALL PROBLEMS EVEN THE ONES WITHOUT DISCUSSIONS, WHICH ARE DESIGNED TO HELP YOU DO RELATED EXERCISES. Each sublist is separated by a semi-colon ";" and ends with the name of the section for those exercises. WE WILL REVIEW THEM IN-CLASS THE LAST WEEK BEFORE FINAL EXAM.
|CH. 22: SEE LECTURE NOTES:|
|CH. 22 MULTIPLE CHOICE TBA - Exercise/problems 1, 3, 5, 11, 12, 13, 19|
|TURN IN: 1, 3, 5, 11, 12, 19|
|* DISCUSSIONS PROVIDED.|
|1. SEE LECTURE NOTES: In a resistor, the current I and voltage VR are in phase: Im = VRm/R, where voltage across R is VR = VRm*cos wt and I = VR/R. Irms = Im/(1.41..), where 1.41... = square root of 2. Note also that Irms = 0.707*Im .|
|3. (a) wL = 1/(wC) Solve for w. (b) Plug in numbers; evaluate wL or 1/(wC) numerically since they are equal.|
|5. Im = VLm/(wL), where VLm = 12.0 (V).|
|11. Use equation 22.18. Vrms2 = VRrms2 + (VLrms - VCrms)2 , where Vrms is the rms value of voltage source. The other rms voltages are given. Evaluate and take the positive square root to get the rms voltage source value.|
|12. Use the formula for impedance Z on page
745, equation 22.22, and set C = infinity, effectively removing C
from the formula.
Z2 = R2 + w2L2. Set w = 2*pi*120 rad/s, where pi = 3.14...and solve for Z. With this value of Z, set (2Z)2 = R2 + w' 2L2 , where w ' is the new frequency doubling the impedance.
|13. Use Z2 =
R2 + (wL - 1/wC)2
(a) Plug in the 3 values of w given and evaluate Z in each case.
(b) Im = Vm/Z, where Z is the total impedance for the RLC series circuit and Vm and Im are the voltage source and current amplitudes. Plug in the 3 values of w given and evaluate Im in each case to answer the question.
(c) Use equation 22.23.
(d) Draw a diagram of the phasors (vectors) like that on page 7 of LECTURE NOTES. The lengths of each voltage vector (phasor) can be easily scaled in your diagram since they are given by VRm = Im*R , VLm = Im*(wL), and
VCm = Im*(1/wC) =(1/ wC)*Im .
|19. See section 22.5 and page 8 of LECTURE NOTES .|