As shown in Fig.(2) at time T/2 the applied voltage is returned to 0. As T RC at time T/2 the voltage across the capacitor is essentially V . For times t > T /2, VC decays exponentially to 0. Let be a very small increment of time. At time t = (T /2 ), VR is almost 0. In this case at time t = (T /2 ) VR has jumped to V . Can you explain why? For t > T /2, VR goes exponentially to 0