# Finding the electic field inside a sphere

In summary, the formula for finding the electric field inside a sphere is E = (Qr)/(4πε<sub>0</sub>r<sup>3</sup>), the direction of the electric field is always radial and the electric field can never be zero. In a conducting sphere, the electric field is zero while in an insulating sphere, it follows the given formula. The electric field inside a sphere can be negative if the charge of the sphere is negative.

## Homework Statement

what is the magnitude and direction of teh electric field just inside the sphere?

E=kq/r^2

## The Attempt at a Solution

i found that the electric field just outside the sphere is 360000vm^-1
i just don't know how to find the field on the inside of the sphere

thank you

## 1. What is the formula for finding the electric field inside a sphere?

The formula for finding the electric field inside a sphere is E = (Qr)/(4πε0r3) where E is the electric field, Q is the charge of the sphere, r is the distance from the center of the sphere, and ε0 is the permittivity of free space.

## 2. How do you determine the direction of the electric field inside a sphere?

The direction of the electric field inside a sphere is always radial, pointing towards the center of the sphere. This means that the electric field lines will be directed from the surface towards the center of the sphere.

## 3. Can the electric field inside a sphere ever be zero?

No, the electric field inside a sphere can never be zero. This is because the electric field is directly proportional to the charge of the sphere, and as long as the sphere has a non-zero charge, there will always be an electric field inside the sphere.

## 4. How does the electric field inside a conducting sphere differ from that of an insulating sphere?

In a conducting sphere, the electric field inside the sphere is zero. This is because the charges in a conducting material are free to move and will distribute themselves in such a way that the electric field inside the sphere is canceled out. In an insulating sphere, however, the electric field inside the sphere will follow the formula mentioned in the first question.

## 5. Can the electric field inside a sphere ever be negative?

Yes, the electric field inside a sphere can be negative if the charge of the sphere is negative. The direction of the electric field will still be pointing towards the center of the sphere, but the negative sign in the formula will result in a negative value for the electric field.

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