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NEET-XII-Physics

33: Thermal and Chemical Effects of Electric Current

with Solutions - page 4
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  • #23
    The potential difference across the terminals of a battery of emf 12 V and internal resistance 2 Ω drops to 10 V when it is connected to a silver voltameter. Find the silver deposited at the cathode in half an hour. Atomic weight of silver is 107.9 g mol-1.
    Ans : Let i be the current through the circuit.
    Emf of battery, E = 12 V
    Voltage drop across the voltameter, V = 10 V
    Internal resistance of the battery, r = 2 Ω
    Applying Kirchoff's Law in the circuit, we get:
    `` E=V+ir``
    `` \Rightarrow i=\frac{E-V}{r}=\frac{12-10}{2}=1\,\mathrm{\,A\,}``
    Using the formula m = Zit, we get:
    `` m=\frac{107.9}{96500}\times 1\times 0.5\times 3600=2.01\,\mathrm{\,g\,}``
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