Electrical Engineering - RLC Circuits and Resonance - Discussion

Discussion :: RLC Circuits and Resonance - General Questions (Q.No.1)

1. 

A 10 resistor, a 90 mH coil, and a 0.015 F capacitor are in series across an ac source. The impedance magnitude at 1,200 Hz below fr is

[A]. 1,616
[B]. 161
[C]. 3,387
[D]. 1,771

Answer: Option A

Explanation:

No answer description available for this question.

Bharamu said: (Jul 27, 2011)  
fr = 1/ 2*Pi*sqrt(L*C)

Rao said: (Oct 25, 2011)  
XL=2*Pi*F*L

Z=Sqrt of(R^2+(XL-XC)^2)

Dinesh said: (Feb 27, 2012)  
fr = 1/ 2*Pi*sqrt(L*C)
(or)
XL=2*Pi*F*L

Z=Sqrt of(R^2+(XL-XC)^2)

Kananya said: (Mar 9, 2012)  
We know that formula for Impedence(Z)
Z=Sqr root of (R^2+(Xl-Xc)^2)
Here R=Resistance
Xl=wl (w=2*3.14*f) and l=inductance of a coil
Xc=1/wc Here c=capacitance of capaciter

Z=Sqr root of (R^2+(Xl-Xc)^2)

Teju said: (Dec 12, 2012)  
XL=WL=(2*PI*f)L
XC=1/WC=1/(2*PI*f)C
where,L=90mh,C=.015microF, f=1200hz and R=10ohm

Z=sqrt of(R^2+(XL-XC)^2)

Rahul Mishra said: (Aug 20, 2013)  
IN RLC SERIES CIRCUITS WE KNOW:

Z = (jw)^2+(jw)R/L+1/LC.

Mrakovic said: (Nov 12, 2013)  
fr = 1/2*pi*sqrt of LC.
fr = 4331.648.

f = fr-1200Hz=3131.64.
Z = sqrt of(R^2+(XL-XC)^2).

Z = 1617 ohm.

Babu said: (Dec 26, 2013)  
We know that,

Resonance frequency:

Fr = 1/2*pi*sqrt(L*C).

Xl = Wl = 2*3.14*f*l.

Xc = 1/wc.

Durai said: (Feb 24, 2014)  
fr = 1/2*pi*sqrt (L*c).

Manindra said: (May 19, 2014)  
Fr = 1/2*pi*sqrt(L*c)=4331.648.
f = fr-1200Hz = 3131.64.

Xl = Wl = 2*3.14*3131.64*l.

Xc = 1/wc.
Z = sqrt of(R^2+(XL-XC)^2) = 1616 ohm.

Aggrey Kere said: (Jun 26, 2014)  
From R-L-C circuit above, we know that; Z=root of R^2+(XL-XC)^2.
but XL=2pi*fr*L.
XC=1/2Pi*fr*C.

Robert said: (Oct 1, 2014)  
XL=2*3.14*F*L THIS IS THE FORMAL.

I WAS ASK TO MAKE SO I CAN FIND UNKNOWN F AND L.

MOVE THING AROUND I CAME UP WITH SO ARE THESE RIGHT.

F=2*PI*L*XL.
L=2*PI*F*XL.

Prashant said: (Jan 20, 2015)  
I think result is not coming from above all formula I want real answer from you friends please reply.

Shwetha said: (Jun 11, 2015)  
Its (xl-xc). Because xl is greater than xc.

Rajat Dey said: (Jun 25, 2015)  
I know above formula but this is very long process and heavy time span. So how can do it quickly? Please help me.

Shailu said: (Aug 7, 2015)  
Is it correct? Above explained examples?

Dinesh said: (Dec 4, 2016)  
Quicker method needed.

Puja said: (Jan 15, 2017)  
Yes, I agree @Prashant.

Siddu Bhandarkavathe said: (Aug 29, 2017)  
It is 1/2 π √ LC.

Hassan said: (Jun 26, 2018)  
How we can change the units?

Sushma said: (Jul 4, 2019)  
1/z = √ [(1/R)^2+(1/Xl-1/Xc)^2] for RLC circuit.

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