Question

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.

Answer 1

The silver deposited at the cathode in half an hour of time is 2.01 g

Explanation:

Let i be the current through the circuit.

Emf of battery, E = 12 V

Voltage drop across the voltmeter, V = 10 V

Internal resistance of the battery, r = 2 Ω

Applying Kirchoff’s Law in the circuit, we get:

E = V+ ir

i = E- $V_r$

  = 12 - 102

  = 1 A

Using the formula m = Zit, we get:

m = 107.996500 × 1 × 0.5  ×3600

   = 2.01 g