Answer to Question #212826 in Electricity and Magnetism for NICKO

Question

(a)Derive an expression for VA − VB, the potential difference between points A and B (b) Does your result reduce to the expected answer when d = 0? When a = 0? and when q = 0.

Answer 1

$V_A=\frac{kQ}{r_A},V_B=\frac{kQ}{r_B}$

$$V_A-V_B=\frac{kQ}{r_A}-\frac{kQ}{r_B}={kQ}({\frac{1}{r_A}-\frac{1}{r_B}})$$

$V_A-V_B=kQ\frac{r_B-r_A}{r_Ar_B}$

When

$$d=r_B-r_A=0;q=Q=0;a=r_A=0$$

Put value then We can written as

$V_B-V_A=0$

$V_A=V_B$