The electric potential V at any point O (x, y, z all in metres) in space is given by V=4x2 volt. The electric field at the point (1m, 0, 2m) in volt/metre is

The electric potential V (x,y,z)=4x2 volt  Now E→=− (i^∂V∂x+j^∂V∂y+k^∂V∂z)Now  and ∂V∂x=8x, ∂V∂y=0  Hence ∂V∂z=0, so at point (1m, 0, 2m)   E→=− 8xi^ or 8 along negative X-axis