Question

The unit of electric field intensity is:
A.)Newton/meter
B.)Coulomb/newton
C.)Newton/coulomb
D.)Joule/newton

Answer 1

Hint: The unit of electric field intensity can be found by using the units of force and charge, as electric field intensity is the force per unit coulomb. Mathematically,
$E=\dfrac{F}{q}$, where E is electric field intensity, F is the force exerted on charge and q is charge.
So, to obtain a unit of electric field intensity we will divide the unit of force and charge.

Complete Step By Step Solution:
The S.I. base units are also known as fundamental units. These include kilogram, second, Ampere, meter, Kelvin, Mole and candela. S.I units of all other physical quantities are derived from them.

Electric field intensity of electric field is the force applied by field on unit coulomb charge. Mathematically we can write

$E=\dfrac{F}{q}$

Electric field is the region around a charged system where it can exert force on another charged particle. It is represented by electric field lines. These lines are also called electric lines of forces. The electric field lines are drawn such that the tangent at a point, will give the direction of force at that point. The density of these lines is proportional to the intensity of electric field strength. No two intersect each other because if they do then force would have two different directions at that point.

The S.I unit of force is Newton and is represented by N.
The S.I unit of charge is Coulomb and is represented by C.
So, S.I unit of electric field intensity will be
Newton/coulomb or N/C
Hence the correct option is C.

Note: Electric field intensity is a derived quantity, so its unit is made from the base S.I. units. Often students confuse electric field intensity with electric field. Electric field is the region around a charged system where it can exert force on another charged particle while electric field intensity of electric field is the force applied by field on unit coulomb charge. Both are not interchangeable. Dimension of electric field intensity is $ML{{A}^{-1}}{{T}^{-3}}$.