Question

Four point charges each having charge Q are located at the corners of a square having sides of length a.

(a) Find a symbolic expression for the total electric potential at the center of the square due to the four charges (Use any variable or symbol stated above along with the following as necessary: k_e.)
V_total =  

  

(b) Find a symbolic expression for the work required to bring a fifth charge p from infinity to the center of the square (Use any variable or symbol stated above along with the following as necessary: k_e.)
W =  

  

Answer 1

We can use identity for potential to find the potential at the center of the square.Note that the potential is a scalar quantity hence it depends only on distance. To find the work done, just multiply the charge with potential. I have use symbol for fifth charge as q.

Also I have used pythagoras theorem to find the distance.

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