Question

a. Which point in Figure EX26.5, 'A' or 'B', has a larger electric potential?

b. What is the potential difference between 'A' and 'B'?

Short answer

a. The point 'A' in Figure EX26.5has a larger electric potential.

b. The potential difference between 'A' and 'B' is $\mathbf{-}\mathbf{70}\mathbf{}\mathit{V}$

Step-by-step solution

Given information and formula used  

Given figure :

Theory used :

1) Electric field lines point from high to low potential.

2) $∆V=-E·dx$

Evaluating which point has a larger electric potential and the potential difference between 'A' and 'B'

(a) 'A' has a bigger potential than 'B' because the electric field lines point from high to low potential.

So,${\mathit{V}}_{\mathbf{A}}\mathbf{>}{\mathit{V}}_{\mathbf{B}}$

(b) The potential difference between 'A' and 'B' is :

role="math" localid="1649498158410" $$\begin{gathered} ∆V=-E·dx \\ \Rightarrow V_B-V_A=-1000\times 7\times {10}^{-2} \\ =\boxed{\mathbf{-}\mathbf{70}\mathbf{}\mathit{V}} \end{gathered}$$