Which of the following is not a unit of electric field intensity?

The correct answer is Option (4) → \( \mathrm{V\,m} \)

The electric field is the force per unit charge, and it is also the potential gradient (potential difference per unit length).

    \( E = F/q \;\Rightarrow\; \mathrm{N\,C^{-1}} \)
    \( E = V/d \;\Rightarrow\; \mathrm{V\,m^{-1}} \)

Since \( 1\,\mathrm{C} = 1\,\mathrm{A\,s} \),

    \( \displaystyle \mathrm{N\,C^{-1}} = \mathrm{N\,(A\,s)^{-1}} = \mathrm{N\,A^{-1}\,s^{-1}} \)

So Options (1), (2) and (3) are all units of electric field. \( \mathrm{V\,m} \) multiplies volt by metre instead of dividing, so it is not a unit of electric field.