Give the relation between electric field and electric potential .

Explanation

Consider a positive charge q kept fixed at the origin. To move a unit positive charge by a small distance dx in the electric field E, the work done is given by dW = -E dx. The minus sign implies that work is done against the electric field. This work done is equal to electric potential difference. Therefore,
dW=dV    (or)   dV=-Edx
Hence E=`-(dV)/(dx)`
The electric field is the negative gradient of the electric potential.