Electrical Engineering - RC Circuits - Discussion

Discussion :: RC Circuits - General Questions (Q.No.19)


In a series RC circuit, when the frequency and the resistance are halved, the impedance

[A]. doubles
[B]. is halved
[C]. is reduced to one-fourth
[D]. cannot be determined without values

Answer: Option D


No answer description available for this question.

Anand said: (Jun 18, 2015)  
Total impedance= R-JXc.

Anonymous said: (Nov 8, 2016)  
Please Given the explanation.

Dhaval said: (May 4, 2017)  
Here, Z=R+Xc.

Now resistance and frequency is halved so R become R/2 and Xc=1/2π(f/2)c => 2Xc=1/2πfc.

Z'=R/2+ 2Xc so impedance neither double nor halved. So, It cannot determine without values.

Manish said: (Oct 3, 2017)  
There is no explanation about capacitance so without value of capacitance we can't say anything.

Noor Ul Islam said: (Aug 30, 2018)  
z =√((2R)^2+(2/wC)^2) because resistance is double and frequency is half.
z = 2√((2R)^2+(2/wC)^2).
So the impedence is double.

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