# Finding the radius of a charged metal sphere

## Homework Statement

A metal sphere centered at the origin has a surface charge density that has a magnitude of 24.6 nC/m2 and a radius less than 2.00 m. At a distance of 2.00 m from the origin, the electric potential is 540 V and the electric field strength is 270 V/m. (Assume the potential is zero very far from the sphere.)

1. What is the radius of the sphere?
2. Is the charge on the sphere positive or negative?

## The Attempt at a Solution

I found the radius as 0.623 m but how do I determine the sign of the charge on the sphere?

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## Answers and Replies

shouldn't the electric field tell you the charge of the particle creating it