In the figure 128 V R1 2680 R2 3070 and R3 4790 What

In the figure ? = 12.8 V, R₁ = 2680 ?, R₂ = 3070 ?, and R₃ = 4790 ?. What are the potential differences (in V) (a)  V_A - V_B, (b)  V_B - V_C, (c)  V_C - V_D, and (d)  V_A - V_C?

Solution

Because of the symmetry, B and C are equipotential points. So we can join B and C and then join R1 and R2 in parallel along side another pair of R1 and R2.

So. a. Va- Vb

TO find that we find the overall resultant resistance and then we will half the voltage to get the voltage about R1.
R = 1430.886 ohm
and V across this R is emf = 12.8 so Va-Vb = 6.4 V

b. Vb-Vc = 0 as they are equipotential points because of mirror image symmetry

c. Vc - Vd = 6.4 Same as the previous one.

d. Va - Vc = 6.4 Same as the previous reasoning