If the frequency of the AC current increases, then the impedance of the series R-C circuit will____:

  1. Increase
  2. Decrease
  3. Remain same
  4. First increase then decrease

Answer (Detailed Solution Below)

Option 2 : Decrease
Free
NDA 01/2025: English Subject Test
5.3 K Users
30 Questions 120 Marks 30 Mins

Detailed Solution

Download Solution PDF

CONCEPT:

Impedance:

  • Impedance is a combination of resistance and reactance. It is essentially everything that resists the flow of electrons within an electrical circuit.

Reactance

  • It is basically the inertia against the motion of the electrons in an electrical circuit.
  • There are two types of reactance:

    1. Capacitive reactance (XC) (Ohms is the unit)

    2. Inductive reactance (XL) (Ohms is the unit)

CALCULATION:

  • The impedance of the series R-C circuit is given as,

\(\Rightarrow Z=\sqrt{R^{2}+X_{c}^{2}}\)     -----(1)

Where R = resistance and Xc = capacitive reactance

  • The capacitive reactance is given as,

\(\Rightarrow X_{C}=\frac{1}{2\pi fC}\)     -----(2)

Where f = frequency of AC current

  • By equation 2 it is clear that when the frequency of the AC current increases, the capacitive reactance will decrease.
  • And by equation 1 it is clear that when the value of Xc decreases, the value of impedance also decreases.
  • So it is clear that when the frequency of the AC current increases, the value of impedance decreases.
  • Hence, option 2 is correct.
Latest NDA Updates

Last updated on May 30, 2025

->UPSC has released UPSC NDA 2 Notification on 28th May 2025 announcing the NDA 2 vacancies.

-> A total of 406 vacancies have been announced for NDA 2 Exam 2025.

->The NDA exam date 2025 has been announced for cycle 2. The written examination will be held on 14th September 2025.

-> Earlier, the UPSC NDA 1 Exam Result has been released on the official website.

-> The selection process for the NDA exam includes a Written Exam and SSB Interview.

-> Candidates who get successful selection under UPSC NDA will get a salary range between Rs. 15,600 to Rs. 39,100. 

-> Candidates must go through the NDA previous year question paper. Attempting the NDA mock test is also essential. 

Get Free Access Now
Hot Links: teen patti 100 bonus teen patti master official teen patti master apk download teen patti vungo