When a choke coil carrying a steady current is short-circuited

PHYSICS · Single correct · AP · Physics C: Electricity and Magnetism · Electromagnetic Induction · Electromagnetic Induction

Problem

When a choke coil carrying a steady current is short-circuited, the current in it decreases to

\beta\,(<1)

times its initial value in a time

t

. The time constant of the choke coil is (a)

\frac{t}{\beta}

(b)

\frac{t}{\ln\left(\frac{1}{\beta}\right)}

(c)

\frac{t}{\ln\beta}

(d)

t\ln\beta