In the circuit shown. $V_{s}$ is a $10\:V$ square wave of period, $T=4\: ms$ with $R=500\: \Omega$ and $C= 10\:\mu F.$ The capacitor is initially uncharged at $t=0,$ and the diode is assumed to be ideal. The voltage across the capacitor $(V_{c})$ at $3\:ms$ is equal to _____ volts (rounded off to one decimal place)