Question

The electric potential V is given as a function of distance x (metre) by V = (5x² + 10x – 9) volt. Value of electric field at x = 1m is

• A. – 20 V/m
• B. 6 V/m
• C. 11 V/m
• D. – 23 V/m

Answer 1

Answer: (A)

– 20 V/m

Answer 2

By using $E = - \frac{dV}{dx}$;

$E = - \frac{d}{dx}(5x^{2} + 10x - 9) = (10x + 10)$,

at x = 1m $E = - 20V ⥂ / ⥂ m$