A heart defibrillator being used on a patient has an RC time constant of 8ms due to the resistance of the patient and the capacitance of the defibrillator. If the initial voltage is 9 kV, how long (in ms) does it take to decline to 6.00 x 10² V?
a. 67.9
b. 54.3
c. 63.8
d. 33.8
e. 21.7
f. 44.5
