Answer:
option D
Step-by-step explanation:
given,
inductance = L = 75 H
initial voltage (V₀) = 12 V
voltage across the inductor to fall to = 3.0 V
time taken to fall of voltage = 2.0 s
Resistance of the circuit = ?
using equation
![V = V_0 e^{(-tR)/(L)}](https://img.qammunity.org/2020/formulas/physics/college/e3f6c812dt8u6qy14yszylsmdjkat5elqr.png)
![3 = 12 e^{(-2 * R)/(75)}](https://img.qammunity.org/2020/formulas/physics/college/2wt940mzpm0oec0sp6k7hdvpywlf20qw3t.png)
![0.25 = e^(-0.02667 * R)](https://img.qammunity.org/2020/formulas/physics/college/orw2kggv3s2aqqegzqfhkbaicoyyvwtoyj.png)
taking ln both side
![ln (0.25) = -0.02667 * R](https://img.qammunity.org/2020/formulas/physics/college/hydybt6ty5776z0djals4ihrskkmyg8i3n.png)
![-1.3863 = -0.02667 * R](https://img.qammunity.org/2020/formulas/physics/college/j5xk88rp8wf04do8ggn5h6le4dckqtsu3k.png)
R = 51.97 Ω
hence, the correct answer is option D