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Nilanjan Bhowmick AIR 3, CSIR NET (Earth Science)
Isha lohan 1
Input is square wave, which means once it charge capacitor then it gives time to capacitor to discharge when it is in off condition. This is dc voltage so it charge capacitor instantly and then discharging curve, and we know that capacitor does not discharge instantly, rather exponentially with time. It is asking in question the curve for current in circuit, as the capacitor get charged and then it discharge through resistor, Here we have to graph the current across resistor, so as capacitor discharge, the current through resistor starts from maximum value and then reduces accordingly. Then as on condition of dc comes, capacitor gets instantly charged and then sends large current to resistor which again decrease. This cycle continues so we get figure 3. So answer is option 3.