S R Let t be the required time since the potential difference across C = across R V cap = V res q/C=iR VC(1-e) = (7) - RC R RC e-IRC 1-e-R = 1 2 e²/ RC =2 t/ RC=In 2 Therefore time t = RC1n2 = (16.062) (13×10° F)ln 2 = 144×10° s = 1 = 0.144ms