Question

Resistance of a voltameter is 2$$\Omega $$, it is connected in series to a battery of 10 V through a resistance of 3$$\Omega $$ . In a certain time mass deposited on cathode is 1 gm. Now the voltameter and the 3$$\Omega $$resistance are connected in parallel with the battery. Increase in the deposited mass on cathode in the same time will be

Answer 1

Correct option is B. 1.5 gm
Remember mass of the metal deposited on cathode depends on the current through the voltameter and not on the current supplied by the battery. Hence by using $$m =Zit$$, we can say $$\dfrac{m_{Parallel}}{m_{Series}}=\dfrac{i_{Parallel}}{i_{Series}}\Rightarrow m parallel = \dfrac{5}{2}\times 1=2.5 gm.$$