Chapter 21 - AC Circuits - Learning Path Questions and Exercises - Exercises - Page 749: 24

a) . (2) $\frac{1}{3}$ b). $200 Ohm$

a) Capacitive reactance = $X_{c}=\frac{1}{2\times 3.14\times f\times C}$ Now, $f'=3f$ Thus, $\frac{X'_{c}}{X_{c}}=\frac{f}{f'}$, Therefore , Since, $f'=3f$, $X'_{c}=\frac{X_{c}}{3}$, so capacitive reactance will be 1/3rd of the original reactance (2) b) $X_{c}=100 Ohm$ $f=120Hz$ When $f'=60Hz$, $X'_{c}=100\times\frac{120}{60}=200Ohm$