d
\(\vec E\, = \,\, - \left[ {\frac{{\partial V}}{{\partial x}}\hat i\,\, + \,\,\frac{{\partial V}}{{\partial y}}\,\hat j\,\, + \,\,\frac{{\partial V}}{{\partial z}}\,\,\hat k} \right]\,\, = \, - ( - 5\,\,\hat i\,\, + \,\,3\,\,\hat j\,\, + \,\,\sqrt {15} \,\,\hat k)\,\,\,\)
\( \Rightarrow \,\,|\hat E|\,\, = \,\,\sqrt {25\,\, + \,\,9\,\, + \,\,15} \,\, = \,\,\sqrt {49} \,\, = \,\,7\,\) યુનિટ