1. An impedance impedance coil has a resistance resistance of 7.5 7.5 ohms and and an inductive inductive reactance reactance of 18 ohms. What is the equation of the voltage wave that produc p roduces es a current of i =11.3 sin wt?
a. 220 sin (wt 0.5!" $. 220 sin (wt 0.#5!"
c. 220 sin (wt 0.#75!" d. 220 sin (wt + 0.375π)
2. A #%&' 0.8 lagging pf pf load is connected to to the end of a short short transmission transmission line where the voltage is 2)0. *f the line resistance and reactance are 0.0% and 0.08 ohm+ respectivel,+ calculate the voltage at the sending end. c. 255 volts a. 225 volts $. 2#5 volts d. 2)5 volts ). What should should $e the the capacitanc capacitance e of a capacitor+ capacitor+ in series series with with a 250&ohm resistor+ that will limit the current to 1.2 amp when the circuit is connected to a %00&volt %0&c,cle sourcec. 6.12µF a. 10.12/ $. 12.12/ d. 8.12/ #. A series circuit consisting of a )0 micro&farad capacitor capacitor and and a 0.155 henr, inductor is connected to a 120&volt %0&c,cle source. alculate the circuit current and indicate whether it lags $ehind or leads the voltage. d. 4 lead a. %.7 lag $. # lag c. %.7 lead 5. A telephone telephone receiv receiver er has an impedanc impedance e of )0% ohms at 800 800 cps and a resistance of %0 ohms. /or what value of capacitance of a capacitor in series with the coil will the power factor $e unit, at 1+000 cpsa. 0.425 $. 0.5#2 c. 0.25# d. 0.#52 %. An && && circuit circuit consists consists of a 55.#&ohm resistor+ resistor+ a 0.17&henr, 0.17&henr, inductor+ inductor+ and an 82.8 micro&farad capacitor. *f the potential drop across the resistor is 72 volts+ calculate the emf of the %0&c,cle source. source. b. 83.4 a. 77.2 c. 55.8 d. 100.8 7. A series circuit consists of of a %%.2 micro&farad capacitor and a varia$le varia$le resistor. /or what two values of resistance will the power ta'en $, the circuit $e 172.8 watts+ if the impressed %0&c,cle %0&c,cle emf is is 120 voltsd. 30 & 53.3 a. #0 3 )).) $. 5).) 3 #0 c. #0 3 )0 8. A series & & circuit ta'es ta'es )71.2 watts at a power power factor of 0.8 0.8 from a 11%&volt 11%&volt %0&c,cle source. What are the values and d. 23.2 & 0.0462 a. )2 )2.8 3 0.05%1 $. 52 52.8 3 0.05%1 c. )2 )2.2 3 0.0%2# 4. he power input to an electric electric motor is 8.8'W when operating normall, from a 2)0&volt a&c source. *f the current is #5 amp under this condition+ calculate the reactive factor. ()5" b. 0.525 a. 0.71% c. 0.855 d. 0.815 10.What value of capacitance will have a capacitive reactance on 180 c,cles that is equal to the %0&c,cle inductive reactance reactance of a 0.0%1&henr, inductor-
a. #8.5 d. 58.5
$. %8.5
c. 38.5
11.At what frequenc, frequenc, will the inductive reactance of a 0.0211&henr, 0.0211&henr, inductor $e equal to the capacitive reactance reactance of a 75µ farad capacitora. 127 ! $. 185 6 c. 117 6 d. 40.7 6 12.A unit, power&factor power&factor load of 1+74# watts is connected in parallel with a load of 1+%5% watts operating at a lagging pf of 0.%. *f the line voltage is 115+ calculate the over all pf. b. 0.842 la" a. 0.40# lag c. 0.5#) lag d. 0.77 lag 1).A coil of wire having a value of (5 8" ohms is connected in series with a capacitive reactance 9c+ and this series com$ination is then connected in parallel with a resistor . *f the equivalent impedance of the circuit is # angle of 0: ohms+ calculate the values 9c and . c. 8 & 20 a. 10 3 # $. # 3 10 d. 20 3 8 1#.A 0.051&henr, inductor is connected in series with a varia$le resistor. /or what value of resistance will the power delivered to the circuit $e a ma;imum if the 1+000&c,cle source has an emf of 40 voltsb. 320 a. 248.75 c. #58 d. 255 15.alculate the susceptance of impedance that is equal to < = ().% #.8" ohms. b. 0.1 a. 0.25 c. 0.02 d. 0.21 1%.A resistor resistor and an inductor are connected in parallel to a 120&volt %0&c,cle source. *f the total current and power in the circuit are+ respectivel,+ 17 amp and 1+800 watts+ calculate the values of and . a. 8 & 0.03#8 $. %.75 3 0.0250 c. 1%.75 3 0.0280 d. 4.25 3 0.0250 17.alculate the equivalent impedance of a circuit in which a coil of wire having a value of 5 angle 5).2: ohms is connected parallel with a capacitive reactance of %.25 ohms. a. 5.)) 5.)) angl angle e )0: )0: $. %.)) %.)) angl angle e #5: #5: c. 8.33 an"le 0$ d. %.)) angle 0: 18.A 10&hp 2)0&volt three phase motor draws a line current of 25 amp when operating at rated output. *f the motor e>cienc, is 41?+ calculate the power factor. c. 0.823 a. 0.775 $.0.757 d. 0.45) 14.What is the voltage of a delta&connected source that delivers an 0.85 power& factor load of 500'w at 1#8 amp-
a. 2%300 2+%%#
$. 2+#50
c. 2+55)
d.
20.A 2)#&volt three&phase source serves a $alanced load consisting of )&equal impedances+ each of which 'as a resistance of ).% ohms and an inductive reac reactan tance ce of #.8 ohms. ohms. alcu alculat late e the the total total power power if the impeda impedanc nces es are are connected in star. c. 5%460 a. %+0#5 $. #+0%5 d. %+5#0