# Find potential inside spherical shell

#### utkarshakash

Gold Member
1. The problem statement, all variables and given/known data
A conducting sphere of radius R has a charge Q. A particle carrying a charge q is placed a distance 2R from the sphere. Find the potential at point A located a distance R/2 from the center of the sphere on the line connecting the center of the sphere and particle q. Note that the charge distribution of the sphere is not symmetrical due to the influence of particle q

3. The attempt at a solution

The potential at point A will be equal to sum of potential due to sphere and charge 'q'.
Due to sphere, V= kQ/R
and due to charge, V= 2kq/5R

But this is not the correct answer.

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#### Tanya Sharma

The potential at point A will be equal to sum of potential due to sphere and charge 'q'.
Due to sphere, V= kQ/R
and due to charge, V= 2kq/5R

But this is not the correct answer.
The item in red is not correct .

#### projjal

1. The problem statement, all variables and given/known data
A conducting sphere of radius R has a charge Q. A particle carrying a charge q is placed a distance 2R from the sphere. Find the potential at point A located a distance R/2 from the center of the sphere on the line connecting the center of the sphere and particle q. Note that the charge distribution of the sphere is not symmetrical due to the influence of particle q

3. The attempt at a solution

The potential at point A will be equal to sum of potential due to sphere and charge 'q'.
Due to sphere, V= kQ/R
and due to charge, V= 2kq/5R

But this is not the correct answer.
Hint:the whole sphere is an equipotential region.

#### SammyS

Staff Emeritus
Science Advisor
Homework Helper
Gold Member
1. The problem statement, all variables and given/known data
A conducting sphere of radius R has a charge Q. A particle carrying a charge q is placed a distance 2R from the sphere. Find the potential at point A located a distance R/2 from the center of the sphere on the line connecting the center of the sphere and particle q. Note that the charge distribution of the sphere is not symmetrical due to the influence of particle q .

3. The attempt at a solution

The potential at point A will be equal to sum of potential due to sphere and charge 'q'.
Due to sphere, V= kQ/R
and due to charge, V= 2kq/5R

But this is not the correct answer.
The reason that V= kQ/R is incorrect for the sphere is highlighted in RED above.

Use the concept of image charges .

#### utkarshakash

Gold Member
Hint:the whole sphere is an equipotential region.
Will the potential at centre be equal to kQ/R due to sphere?

#### projjal

Will the potential at centre be equal to kQ/R due to sphere?
Yeah.

You also know the potential at centre due to charge q and wid that you get the answer.

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