Why Is Q Positive in Charge Balancing Equations?

[flyingpig]

Homework Statement

[PLAIN]http://img256.imageshack.us/img256/9025/93408370.jpg

The Attempt at a Solution

Shouldn't it be 2Q + x = -Q

x = -3Q?

My book say it is +Q

 

[betel]

+Q is correct.
What would happen to the single electrons carrying the charge if you joined the two spheres by a conducting wire?

 

[flyingpig]

+Q is correct.
What would happen to the single electrons carrying the charge if you joined the two spheres by a conducting wire?

Then why am I wrong? 2Q + x = -Q?

 

[gneill]

Don't you mean 2Q + (-Q) = x = +Q ?

After all, the total enclosed charge in a Gaussian surface surrounding both spheres would contain a net charge of +Q.

 

[rwisz]

because the charge on the left side is negative and the charge on the right side is positive. Can someone explain why this is?

I can provide an explanation for why the Q in this equation is positive. It is important to understand that the sign of a charge represents the type of charge, not necessarily the magnitude. In this case, the negative sign on the left side of the equation indicates that the charge is negative, while the positive sign on the right side indicates that the charge is positive.

Now, let's consider the overall charge of the system. The left side has a charge of -2Q, while the right side has a charge of -Q. In order for the overall charge of the system to be balanced, the right side must have a greater positive charge than the left side has negative charge. This is why the Q in the equation is positive - it represents the additional positive charge needed to balance the system.

In summary, the Q in this equation is positive because it represents the additional positive charge needed to balance the overall charge of the system. It is important to remember that the sign of a charge represents the type of charge, not necessarily the magnitude.