Flag Electromagnetic Induction> a q charge is distributed over two concen...
question mark

a q charge is distributed over two concentric spherical shells of radius r and R (R>r) and having same surface charge densities . find the potential at the common centre of the shell
 

6ix9ine , 5 Years ago
Grade 12
anser 2 Answers
Arun

Last Activity: 5 Years ago

 
By superposition princpiple, potential at the common centre is equal to algebraic sum of potentials at centre due to each sphere.
 
If we want the potential of a sphere, we need the radius (given) and the charge on it (which is what we should find now).
If the total charge is Q, then let’s assume charge of small sphere si q1, and large sphere is q2.
Thus Q = q1 + q2
 
It is given that the surface charge density is the same, thus:
(q1)/(4*pi*r^2) = (q2)/(4*pi*R^2).
Therefore,
q1 = (r^2)(q2)/(R^2)
 
But q1 + q2 = Q,
therefore,
q2 = Q(R^2)/(r^2 + R^2),
and similarly (from the same equation,
q1 = Q(r^2)/(r^2 + R^2).
Potential at common centre is now given as:
k(q1)/r + k(q2)/R.
 
Substituting previously found values, this becomes:
k(Q)(r+R)/(r^2 + R^2).
 
Regards
Arun

Khimraj

Last Activity: 5 Years ago

charge density=q/4(3.14)r=Q/4(3.14)R.
ie, q=Q*r*r/R*R.
potential at center of shell=kq/r+kQ/R
kQ/R(r/R+1)
Q=charge density*4(3.14)R*R
on simpilfying,
V=charge density*(r+R)/epsilon

Provide a better Answer & Earn Cool Goodies

Enter text here...
star
LIVE ONLINE CLASSES

Prepraring for the competition made easy just by live online class.

tv

Full Live Access

material

Study Material

removal

Live Doubts Solving

assignment

Daily Class Assignments


Ask a Doubt

Get your questions answered by the expert for free

Enter text here...