Use app×
Join Bloom Tuition
One on One Online Tuition
JEE MAIN 2025 Foundation Course
NEET 2025 Foundation Course
CLASS 12 FOUNDATION COURSE
CLASS 10 FOUNDATION COURSE
CLASS 9 FOUNDATION COURSE
CLASS 8 FOUNDATION COURSE
0 votes
412 views
in Physics by (239k points)
closed by

Which of the following statement is correct:

a) If the frequency of the AC current increases, the impedance of the RC circuit increases

b) If the frequency of the AC current increases, the impedance of the RL circuit increases

c) If the frequency of the AC current increases, the impedance of the circuit containing only resistance will increase


1. Only a is correct.
2. Only b is correct.
3. Only c is correct.
4. Both a and b are correct

1 Answer

0 votes
by (237k points)
selected by
 
Best answer
Correct Answer - Option 2 : Only b is correct.

CONCEPT:

  • Resistor: It is an electrical component that has two terminals and it is used for either limiting or regulating the flow of electric current in electrical circuits.
  • Inductor: Inductors are coil-like structures that are used in electrical circuits. The coil is an insulated wire with a central core. An inductor is used to store energy in the form of magnetic energy when ac electricity is applied to the circuit. One of the main properties of an inductor is that it opposes the change in the amount of current flowing through it.
  • Capacitor: A capacitor is a device that is used for the temporary storage of energy in circuits and can be made to release it when required.
  • Reactance: It is basically the inertia against the motion of the electrons in an electrical circuit.
  • Reactance is of two types:
    1. Capacitive reactance
    2. Inductive reactance

\(⇒ X_{C}=\frac{1}{2\pi fC}\)

⇒ XL = 2πfL

Where f = frequency of ac current, C = capacitance of the capacitor, and L = self-inductance of the coil

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

EXPLANATION:

  • The impedance of the RC circuit is given as,

\(⇒ Z=\sqrt{R^{2}+X_{C}^{2}}\)      -----(1)

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

  • From equation 2 it is clear that if the frequency of the AC current increases, the value of XC decreases.
  • So by equation 1, it is clear that when the vale of XC decreases, the impedance of the RC circuit also decreases.

The impedance of the RL circuit is given as,

\(⇒ Z=\sqrt{R^{2}+X_{L}^{2}}\)      -----(3)

⇒ XL = 2πfL     -----(4)

  • From equation 4 it is clear that if the frequency of the AC current increases, the value of XL also increases.
  • So by equation 3, it is clear that when the vale of XL increases, the impedance of the RL circuit also increases.

The impedance of the circuit containing only resistance is given as,

⇒ Z = R

Where R = resistance in ohm

  • We know that the value of resistance does not depend on the frequency of the AC current, so the impedance of the circuit containing only resistance is independent of the frequency of the AC current. Hence, option 2 is correct.

Welcome to Sarthaks eConnect: A unique platform where students can interact with teachers/experts/students to get solutions to their queries. Students (upto class 10+2) preparing for All Government Exams, CBSE Board Exam, ICSE Board Exam, State Board Exam, JEE (Mains+Advance) and NEET can ask questions from any subject and get quick answers by subject teachers/ experts/mentors/students.

Categories

...