388 ELEMENTS OF ELECTRICAL ENGINEERING. 



cal ohms, (&) 0.03 1 1 reciprocal ohms, (c) 0.0909 reciprocal 

 ohms. 



Note. The values of conductance, susceptance, and admittance are expressed in 

 terms of a unit which is the reciprocal of the ohm, just as the conductivity (reciprocal 

 of the resistance of a circuit) is expressed in terms of the reciprocal of the ohm. 



38. An inductance of 0.08 henry and a condenser of 25 micro- 

 farads capacity are connected in series, the resistance of the circuit 

 being 7 ohms, (a) What is the critical frequency of the circuit, 

 that is to say, at what frequency does resonance occur? (b) What 

 is the effective value of the electromotive force across the con- 

 denser terminals when an electromotive force of 1 1 o volts at the 

 critical frequency acts upon the circuit? Ans. (a) 112.5 cycles 

 per second, (b) 88.8.9 volts. 



39. An inductance of o. 12 henry and a condenser of which the 

 capacity is 25 microfarads are connected in parallel. The resist- 

 ance of the inductive circuit is 6 ohms and the resistance of the 

 condenser circuit is I ohm. What is the critical frequency at 

 which resonance occurs? Ans. 91.9 cycles per second. 



40. An inductance of o. I henry and a resistance R are con- 

 nected in series to 1 1 o-volt 6o-cycle mains. Calculate the cur- 

 rent values when R equals zero, when R equals one ohm, 

 when R equals 5 ohms, when R equals 10 ohms, when R 

 equals 20 ohms, when R equals 50 ohms, and when R equals 

 100 ohms, and plot a curve of which the abscissas represent R 

 and the ordinates represent corresponding values of the current. 

 Ans. 2.918 amperes, 2.917 amperes, 2.893 amperes, 2.821 

 amperes, 2.578 amperes, 1.757 amperes, and 1.029 amperes. 



41. A non-inductive resistance of 20 ohms, a resistance-less 

 inductance of 0.06 henry, and a condenser of 105 microfarads 

 capacity are connected in series to 1 1 o-volt 6o-cycle mains. Find 

 the electromotive force, (a) between the terminals of the resist- 

 ance, (b) between the terminals of the inductance, and (c) be- 

 tween the terminals of the condenser. Ans. (a) 109.0 volts, (b) 

 123.3 volts, (c) 137.8 volts. 



42. A transmission line of which the resistance is 4 ohms and 



