The electric field is a vector field with SI units of newtons per coulomb (N C^?1) or, equivalently, volts per meter (V m^?1). The direction of the field at a point is defined by the direction of the electric force exerted on a positive test charge placed at that point. The strength of the field is defined by the ratio of the electric force on a charge at a point to the magnitude of the charge placed at that point. Electric fields contain electrical energy with energy density proportional to the square of the field intensity. The electric field is to charge as acceleration is to mass and force density is to volume.

actually question is

 

 

What is the electric field due to a uniformly charged circular disc of radius r at a distance d from centre in the plane of disc?

Well,

 

Here what u need is the electric field due to a stright line of finite length.

 

which is :

 

E due to a stright rod of length L, E = (kQ/ld) [ sint₁ + sint₂ ]

 

The various quantities are as shown in attached diagram fig. 1.

 

The question's diagram is as shown in fig. 2

 

Now, consider a strip in the disc of very small thick ness dx

 

So, charge per unit area = Q/(pie*r²)

 

So, charge on a strip of area = Rdx [ rectangular strip ]

 

charge = QRdx/(pie*r²)  ------------------------- Eq.1

 

So, electric field produced by the strip

 

dE = kQ/ld [ sint₁ + sint₂ ]

     = (k/ld) * [QRdx/(pie*r²)] * [ 0 + d/(d²+r²)^1/2]

 

integrate it by taking the limits as 2(pie)r i.e the circumference.

 

 

 

 

Now, i hope i am crrect. do tell me in case of problems.

oops !!!! srry !!!!!

give me amin, let me find out. now, i woudn't delete this solution. maybe of any help to someone

Srry, buddy !!!! i give up !!

 

can't get it !!!

 

Getting highly complex !!!