If resistance is 20 Q. and inductance is 27 in a R-L series circuit, then time constant of this circuit will be________?

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 s
B. 0.1 s
C. 10 s
D. 100 s