Question

In an RL series circuit, the maximum current
is 0.7 A. After the switch is thrown, a current
of 0.25 A is reached in 0.15 s, and then the
voltage across the resistor is 25 V. Calculate the inductance for this circuit.
Answer in units of H

Answer 1

I'm using the i=E/R(1-e^-t/Tl) formula but I keep ending up with ln(0)