How does electric potential relate to point charges in homework problems?

[WeiLoong]

Homework Statement

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Homework Equations

Electric potential

The Attempt at a Solution

Is electric potential a vector quantity?
So that mean both charges product electric potential and result in zero at P?
How should i start for question 17a?

 

[cnh1995]

Is electric potential a vector quantity?

No. It is scalar.

 

[QuantumQuest]

Electric potential is a scalar. Now, what does it mean that potential at P is zero? You have two isolated point charges, that each one produces an electric field around it. So, how can the potential at P be zero? Answering that, you can immediately see that using this fact and a simple formula, you can calculate point charge at B.

 

[WeiLoong]

Electric potential is a scalar. Now, what does it mean that potential at P is zero? You have two isolated point charges, that each one produces an electric field around it. So, how can the potential at P be zero? Answering that, you can immediately see that using this fact and a simple formula, you can calculate point charge at B.

That mean kq/r+kq/r=0 something like that?

 

[QuantumQuest]

That mean kq/r+kq/r=0 something like that?

What would be the potential at point P, if you didn't have point charge at B? But you have this point charge at B and potential at P is zero. So, you have a zero from two scalars (V). What does this imply for the second potential (i.e. regarding B)?