In the $LR$ circuit shown,what is the variation of the current $I$ as a function of time? The switch is closed at time $t = 0 \, s.$

  • A
    $\frac{V}{R}\left( {1 - {e^{ - \frac{{Rt}}{L}}}} \right)$
  • B
    $\frac{V}{R}\,\,{e^{ - \,\frac{{Rt}}{L}}}$
  • C
    $-\frac{V}{R}\,\,{e^{ - \,\frac{{Rt}}{L}}}$
  • D
    None

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