Question

Two cells of e.m.f 1.25 V , 0.75 V and each of internal resistance 1 ohm are connected in parallel. The effective voltage will be

Answer 1

Please see the circuit diagram.

we want the Voltage difference V_AB.

let A and B be open and not connected to any thing.

There is a current that flows from cell of larger emf to the cell of small emf.

Call that current as  I Amperes.

     1.25 V - 0.75 V - I * R2 - I * R1 = 0
         I = 0.5 / (R1+R2)
      
     V_AB =  -0.75 - I * R2 =  - 0.75 - 0.5 * R2 / (R1+R2)
                 = - (0.75 R1 + 1.25 R2) / (R1+R2)
                 = - ().75 * 1 + 1.25 * 1) / (1 + 1)  volts
                 =  - 1 volts

Answer 2

Explanation:

Hope this helped u.

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