Understanding the concept of the Electric field due to point charge involves the basic understanding from the simplest levels. This involves understanding electric fields, the concept of current, charge and the basics of all physics related to such concepts.
So, basically, we will be touching upon all aspects to answer your question, “What is electric field due to point charge?“
What is physics?
The branch of science deals with the study of matter and the interactions between the fundamental constituents distinguished in the Universe. Explained in simpler terms, physics is concentrated to cover all characteristics of nature of both the macroscopic and submicroscopic levels.
The study of physics covers the behaviour of objects under any particular action and involves the natural forces, which include the gravitational, electromagnetic, and nuclear forces in fields. The sole objective of physics is to formulate some comprehensive concepts which bind together and describe many such disparate events.
To better understand the electric field and its behaviour due to any charges, we should first understand the electrostatic forces, which are crucial in the better conception of the Electric field.
What are electrostatic forces?
The branch of physics which deals with the study of electric charges in a resting position is termed electrostatics. It has been observed that some materials like amber attract lightweight particles after rubbing. Sometimes, rubbing a glass rod against silk also creates the same effect. The glass rod obtains the attributes of attracting the objects like a few bits of paper towards it during the process. The attraction is observed when the discharge of electric charges happens. It occurs due when insulating surfaces are rubbed together. Wherever the Electric charge is available, it has a property to accompany the fundamental particle.
It is seen that whenever an electric charge is held very close to another charge Q,
they can experience a force of repulsion or can have a force of attraction. It goes without saying that the force set up is due to the electric field surrounding the charge Q. The arousal of electrical phenomena is due to the forces which electric charges apply to each other. These forces can be explained by Coulomb’s law.
What is an electric field?
The electric properties associated with every point in space in the presence of charge in any form are termed the electric field. Being a vector quantity by nature, it possesses both magnitude and direction and is expressed with an E value known as the electric field strength or can also be identified as electric field intensity.
Rather than contemplating the electric force through the direct interaction between the two electric charges, which are present at a distance from each other, one charge is regarded as a source of an electric field that has extended outwards the surrounding space. On the other hand, when the force is applied on the second charge in space, it is observed that direct interaction of the electric field with the second charge happens.
At any given point, if the strength of any given electric field such as ‘E’ is applied, it may be termed as the electric field. Force F is exerted on a per unit positive electric charge. At that point, ‘q’ will be presented as E = . If the present second charge is greater by two times, the resultant force becomes twice. However, the quotient of the electric field E’s measure remains the same all the time. Source charge is responsible for the strength of the electric field and not the test charge.
Alternatively, the electric field might be defined as the force which has a per unit positive charge that would be applied ahead of the field is interrupted by the existence of the test charge. The electric field due to a charge Q at a particular point in space may be the force that has a unit of positive charge. It could also be experienced if it is placed at a particular point. The charge Q, which produces an electric field, known as a source charge, and the charge q, which tests the effect of a source charge, is called the test charge. Charge Q producing electric field at a given point r is:
E (r) = r =
r
Where r = , which is a vector unit from the origin to the point r,
F =
r
Assuming the SI unit of the electric field as N/C.
If a charge q is brought around at any point near Q, Q itself experiences an electrical force due to q and will gradually move away. It is one of the ways to make q look very small. The force F also is negligibly small, but the ratio is finite and forms the definition of the electric field, which is expressed as:
E =
The formula for electric field due to a point
The English scientist Michael Faraday was the one who had an immense contribution in the field of sciences of electromagnetism and electrochemistry, along with the findings in diamagnetism, electromagnetic induction, and electrolysis was first to introduce the concept of the field.
He further concluded through his research that the electric field intensity at any point is the strength of the electric field at that particular point. It is further defined as the force observed by a unit positive charge when placed at a particular point.
Examples of electric fields due to a point charge
Considering a calculation of electric field intensity, or we can say the strength of P at any point because of a point charge Q at O.
OP equals r, let us consider it as a small positive charge at P and according to Coulomb’s law, the interaction of force between the charges
and Q at P are,
\[F = \frac{1}{4\pi \epsilon_{0}} Q \frac{q_{0}}{r^{2}} (r)\]
Where r is a unit vector directed from Q towards
We know,
\[\overrightarrow{E}(\overrightarrow{r}) = \overrightarrow{F} (\overrightarrow{r})\]/q₀
Problem 1: The electric field given at a point because of a point charge is 40N/C, and the electric potential at that point is 20J/C respectively. What is the distance of the point from the charge and the magnitude of the charge?
Solution:
For point charge,
E =
Given,
V = 20J /C
E = 40 N/ C
Distance from point charge, r = ?
Point charge q =?
R =
=
= 0.5 m
V =
q = 4 V
q = x .5 x 20
q = .11 x C
q = .11nC
Conclusion
These were the basics surrounding electric fields due to point charge. If you wish to learn more, you can browse through Vedantu for more informative articles on the topic for easy learning.
