Answer: 1.95
Explanation:
You should start off from the decay formula and solve for τ:
[tex]I = I_{0}e^{\frac{t}{\tau\\ } }[/tex]
[tex]\frac{I}{I_{0}} = e^{\frac{-t}{\tau} }[/tex]
Apply inverse logarithmic function:
[tex]ln(\frac{0.2 A}{1.2 A} ) = \frac{-t}{\tau}[/tex]
The final form will be:
[tex]\tau=\frac{-3.5s}{ln(\frac{0.2A}{1.2A} )}[/tex]
Inputing values for I, IO, and t:
[tex]\tau=\frac{-3.5S}{ln(\frac{0.2 A}{1.2 A} )} = 1.95[/tex]
