Question

The electric potential decreases uniformly from 120 V to 80 V as one moves on the X-axis from $x=-1cm$ to $x=+1$ cm. The electric field at the origin.

• A. must be equal to $20V/cm$
• B. must be equal to $2.0V/cm$
• C. must be greater than $20V/cm$
• D. must be less than $20V/cm$

Answer 1

The correct option is C must be greater than $20V/cm$

E = -dV/dx

Since V decreases uniformly, E = -ΔV/Δx

= -(80 - 120)/{1- (-1)}

= - ( -40)/2

= 20 V/Cm in the positive direction of x axis