Why the method of doing these 2 question are not the same ? Please help!!

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1 Answer
Jane
Feb 25, 2018

Please see below

Explanation:

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The formula I have used is,when two cells of emf #E_1# and #E_2# with their respective wire resistance of #r_1# and #r_2# are arranged as shown in the problem,net voltage of the circuit becomes,

#E = ((E_1)/(r_1) + (E_2)/(r_2))/((1/(r_1)) + (1/(r_2))#

You can derive this using Kirchoff's law

This is valid only when the polarity of the cells are as same as shown in the problem

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