Consider applying a unit ramp voltage source to a series RL circuit as shown in <image 1>. Compute the voltages $v_R (t)$ with zero initial condition for L = 0.1H;
['t + (1 / 10) (e^{-20t} - 1) V', 't + (1 / 20) (e^{-10t} - 1) V', 't + (1 / 10) (e^{-10t} - 1) V', 't - (1 / 10) (e^{-10t} - 1) V']