Question

In Fig. 1.85, calculate the values of (i) V_AF (ii) V_EA and (iii) V_FB

Answer 1

It should be noted that V_AF stands for the potential of point A with respect to point F. The easiest way of finding it is to start from the reference point F and go to point A along any available path and calculate the algebraic sum of the voltages met on the way. Starting from point F as we go to point A, we come across different battery voltages. Taking the sign convention given in Art. 1.28, we get 

(i) V_AF = − 24 + 4 + 8 − 6 + 12 = − 6V 

The negative sign shows that point A is negative with respect to point F by 6V. 

(ii) Similarly, V_EA = − 12 + 6 − 8 − 4 = − 18 V 

(iii) Starting from point B, we get V_FB = 6 − 8 − 4 + 24 = 18V. 

Since the result is positive it means that point F is at a higher potential than point B by 18V