Question

3. In an electrolysis experiment, the ammeter records a steady current of 1 A. The mass of copper deposited in 30 minutes is 0.66 g. Calculate the error in the ammeter reading. [Electrochemical equivalent of copper = 0.00033 g C⁻¹]

Accepted Answer

Given: ammeter reading = 1A, mass of copper deposited m = 0.66g, time t = 30min = 1800s, electrochemical equivalent of copper z = 0.00033 g/C.
m = zIt, so the current actually passed, I = m/(zt) = 0.66/(0.00033×1800) = 1.111 A.
Error in ammeter reading = (current passed) − (ammeter reading) = 1.111 − 1 = 0.111 A.

WAEC Physics 2013 Theory — Question 3

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