In Electrostatics (Class 12 Physics), establishing the mathematical relationship between the Electric Field (E) and Electric Potential (V) is a highly important derivation and concept.
Because of this relationship, the unit of Electric Field can be written not only as Newtons per Coulomb (N/C) but also as Volts per metre (V/m).
The relation is expressed by the formula:
E = - dV / dr
Where:
The negative sign (-) in the formula E = -dV/dr is extremely important.
It indicates that the direction of the Electric Field is always in the direction of decreasing electric potential. In other words, an electric field always points from a higher potential region to a lower potential region.
Based on the formula, the electric field intensity at any point is equal to the negative of the potential gradient at that point.
An equipotential surface is a surface where the electric potential (V) is constant at all points. Therefore, the potential difference (dV) between any two points on it is zero.
What is the SI Unit of Force? (Newton)
Learn the SI unit of force in Physics. Understand why the unit is called Newton, its definition from F=ma, and examples of force in daily life for Class 9.
What is a Virtual Image? (Optics - Class 10)
Learn what a virtual image is in Physics. Understand the difference between real and virtual images, which mirrors form them, and examples from daily life.
When Will a Diver Experience Greater Pressure?
A diver experiences greater pressure at greater depth. Pressure = P₀ + ρgh. Every 10 m depth adds ~1 atm (101 kPa) of pressure in seawater.
Who is the Father of Physics? (Galileo, Newton, and Einstein)
Find out who is known as the father of physics. Learn about the contributions of Galileo Galilei, Isaac Newton, and Albert Einstein to physical sciences.
Why are Sound Waves Called Mechanical Waves?
Learn why sound waves are called mechanical waves in Physics. Understand what a medium is, longitudinal wave nature of sound, and why sound cannot travel in vacuum.
Turn this guide into revision flashcards, a practice exam, or an AI-generated podcast — free, no signup required.