What is the net electric field at point P in this physics problem?

[Burger]

Physics Problem , please help I'm writing a test tomorrow and want to know if I'm right.
The Question :

Two point charges Q1 and Q2 are spaced 3m apart.

Q1's charge = 14C
Q2's charge = +20 C

*Q1 -------(3meters)------- *Q2 ----(2meters)---- *P

Calculate the net electric field at point P, 2m right from where Q2 is situated?


My Calculations :

Q1 on P = -5.04 x10^9
Q2 on P = 4.5 x10^10

Final answer = Net : 3.996x10^10


Formula used:

E = (k*Q)/r^2

 

[TSny]

Hello, Burger. Welcome to PF!

Did you forget to include the sign of Q1 when you stated Q1 = 14 C?

It is important to always include units with your answers.

Just to be sure that you have a full understanding, what is the interpretation of the negative sign for your answer for the electric field of Q1 at P?

Finally, electric field is a vector. So, it has a magnitude and a direction. Therefore, your final answer for the field at P should include both a magnitude and a direction. The direction should be clearly stated and not left to the reader to interpret.

Otherwise, your numbers look good! (You're getting a very large answer because a Coulomb is a huge amount of static charge.)

 

[Burger]

Q1's charge = -14 C

Thanks for the help! Will ace the Test hopefully. I must just remember to include the direction the N•C^-1

 

[TSny]

OK. Good luck with the test!

 

[HalfLostAndSearching]

Based on your calculations, it seems that you have correctly applied the formula for electric field, which is E = (k*Q)/r^2. This formula takes into account both the magnitude of the charge and the distance between the charges. It appears that you have taken into account the distance from both Q1 and Q2 to point P, and have correctly calculated the electric field at that point. Your final answer of 3.996x10^10 is in units of Newtons per Coulomb, which is the unit for electric field. Therefore, it seems that your calculations are correct and you have found the net electric field at point P in this physics problem. Good luck on your test tomorrow!