If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be________? December 11, 2018 – by admin If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be________? A. 0.001 sB. 0.1 s C. 10 s D. 100 s