Finding the Net charge

sheri1987

1. Homework Statement

A metal sphere has a charge of +8.0 µC. What is the net charge after 9.00 *10^13 electrons have been placed on it?

2. Homework Equations

q=Ne where q is the charge, N is the number of electrons, and e is given as 1.6*10^-19

3. The Attempt at a Solution

Well the problem gives us a charge, q, and the N, number of electrons, so I figure somehow I need to use this equation. I am not sure where to start though, could someone get me started? Thanks!

Related Introductory Physics Homework Help News on Phys.org

Kurdt

Staff Emeritus
Gold Member
The electrons have a negative charge. That charge will be given by the product of the number of electrons and the charge of the electrons. Since the sphere starts with a positive charge the net charge will be the initial positive charge plus whatever charge all the electrons have. Be careful with signs here.

sheri1987

I'm still having trouble...what number needs to be negative?

Kurdt

Staff Emeritus
Gold Member
Electrons have a negative charge.

Physics Forums Values

We Value Quality
• Topics based on mainstream science
• Proper English grammar and spelling
We Value Civility
• Positive and compassionate attitudes
• Patience while debating
We Value Productivity
• Disciplined to remain on-topic
• Recognition of own weaknesses
• Solo and co-op problem solving