Class 12 Exam  >  Class 12 Questions  >  In a series resonant L_C_R circuit, if L is i... Start Learning for Free
In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency will
  • a)
    Increase by 10%
  • b)
    Decrease by 10%
  • c)
    Remain unchanged
  • d)
    Increase by 2.5%
Correct answer is option 'C'. Can you explain this answer?
Verified Answer
In a series resonant L_C_R circuit, if L is increased by 25% and C is ...
v0=1/2π√(LC)
⇒In this question,
L’=L+25% of L
=L+(L/4)=5L/4
And C’=C-20% of C
=C-(C/5)=4C/5
Hence, v0=1/2π√(L’C’)
=1/2π√[(5L/4) x (4C/5)]
=1/2π√(LC)=v0
The answer is option C, remains unchanged.
 
View all questions of this test
Most Upvoted Answer
In a series resonant L_C_R circuit, if L is increased by 25% and C is ...
Free Test
Community Answer
In a series resonant L_C_R circuit, if L is increased by 25% and C is ...
Resonance is a phenomenon that occurs in LCR circuits when the inductive reactance (XL) and capacitive reactance (XC) are equal. At resonance, the circuit exhibits maximum impedance and maximum current. The resonant frequency (fr) is the frequency at which this occurs.

Let's analyze the effect of increasing the inductance (L) by 25% and decreasing the capacitance (C) by 20% on the resonant frequency.

Effect of increasing the inductance (L) by 25%:
- Inductive reactance (XL) is directly proportional to the inductance (L). Therefore, if L is increased by 25%, XL will also increase by 25%.
- As XL increases, the impedance of the circuit also increases.
- Since resonance occurs when XL = XC, increasing XL will shift the resonant frequency to a higher value.

Effect of decreasing the capacitance (C) by 20%:
- Capacitive reactance (XC) is inversely proportional to the capacitance (C). Therefore, if C is decreased by 20%, XC will also decrease by 20%.
- As XC decreases, the impedance of the circuit also decreases.
- Since resonance occurs when XL = XC, decreasing XC will shift the resonant frequency to a lower value.

Combining the effects of increasing L and decreasing C:
- The increase in XL and the decrease in XC will have opposite effects on the resonant frequency.
- However, the magnitudes of the changes are different (25% increase vs. 20% decrease).
- The magnitude of the change in L is greater than the magnitude of the change in C.
- Therefore, the net effect of increasing L and decreasing C is to shift the resonant frequency to a lower value.

Therefore, the resonant frequency will remain unchanged when L is increased by 25% and C is decreased by 20%. Option 'C' is the correct answer.
Explore Courses for Class 12 exam

Top Courses for Class 12

Question Description
In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? for Class 12 2025 is part of Class 12 preparation. The Question and answers have been prepared according to the Class 12 exam syllabus. Information about In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? covers all topics & solutions for Class 12 2025 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer?.
Solutions for In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? in English & in Hindi are available as part of our courses for Class 12. Download more important topics, notes, lectures and mock test series for Class 12 Exam by signing up for free.
Here you can find the meaning of In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? defined & explained in the simplest way possible. Besides giving the explanation of In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer?, a detailed solution for In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? has been provided alongside types of In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? theory, EduRev gives you an ample number of questions to practice In a series resonant L_C_R circuit, if L is increased by 25% and C is decreased by 20%, then the resonant frequency willa)Increase by 10%b)Decrease by 10%c)Remain unchangedd)Increase by 2.5%Correct answer is option 'C'. Can you explain this answer? tests, examples and also practice Class 12 tests.
Explore Courses for Class 12 exam

Top Courses for Class 12

Explore Courses
Signup for Free!
Signup to see your scores go up within 7 days! Learn & Practice with 1000+ FREE Notes, Videos & Tests.
10M+ students study on EduRev