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

AI Thread Summary
The discussion focuses on calculating the net electric field at point P, located 2 meters to the right of charge Q2, which is 3 meters apart from charge Q1. The charges are Q1 = -14 C and Q2 = +20 C, resulting in calculated electric fields of -5.04 x 10^9 N/C from Q1 and 4.5 x 10^10 N/C from Q2. The final net electric field is approximately 3.996 x 10^10 N/C. Participants emphasize the importance of including the sign of the charges and the direction of the electric field in the final answer. The conversation concludes with encouragement for the test-taker to remember these details for their upcoming exam.
Burger
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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
 
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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.)
 
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
 
OK. Good luck with the test!
 
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