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GATE 2014 EC (EC1) – Question 43

Networks, Signals and Systems · Time and Frequency Domain Analysis of Linear Circuits · 2 marks · Numerical answer

For the circuit shown, find capacitance C (mF) giving critically damped current response i(t).

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Correct answer: 9.99 to 10.01

Explanation

For a series RLC circuit the characteristic equation is s²+(R/L)s+1/(LC)=0. Critical damping requires (R/L)²=4/(LC), giving C=4L/R². With L=4H and R=40Ω, C=16/1600=0.01F=**10mF**.