Physics Paper 2, May/June 2012  
Questions: 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 Main
General Comments

Question 4

           (a) Explain the term electrodes in electric cells
(b) An electric current passing through an electrolyte for 2minutes deposited200u of a substance If the electrochemical equivalent of the substance is 8.33x10'4gC', calculate the current passed


The explanation was well attempted but the calculation was poorly rendered by few responding candidates due to poor handling of the exponential figure. Some candidates substituted wrongly. They are supposed to convert the time given from minutes to the S.I unit which is seconds before substituting into the formula. Performance was on the average.
The expected answers are:

  1. An electrode is a conductor through which electrons flow into or out of the

Electrolyte (of a cell) Any other correct additional information e.g. electrodes can be positive or negative or metals
(b) m = zlt or       1 = m
                 =                        200
8.33 x 10_4x2x60

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