Find a point charge a distance form a charged rod

[rocapp]

Homework Statement

See image

Homework Equations

KQ/r^2

The Attempt at a Solution

I have seen several different ways of working this problem, but they have all failed on me.

I tried this using the equation above from my book

E = (8.99x10^9)(1036 C)/(4x10^-6m)

E= 2.328x10^18 N/C

I also tried using

E = K*Q/sqrt(r^2+(L/2)^2)
E = 1.86x10^11 N/CThis was not correct. Please help. Thanks in advance!

 

[ehild]

Read the problem text. You have to find the electric field at a distance from the rod (not a point charge).

See http://hyperphysics.phy-astr.gsu.edu/hbase/electric/elecyl.html

ehild

 

[rocapp]

Thanks! The answer is 5.3x10^13N/C

 

[ehild]

Correct.

ehild

 

[Nickie]

Hello,

I can see that you have attempted to solve this problem using the equations provided in your book. However, it seems like you may be using the wrong values for the distance (r) and the charge (Q).

Firstly, the distance (r) should be the distance between the point charge and the center of the rod, which in this case is 4x10^-6m. Secondly, the charge (Q) should be the charge of the rod, which in this case is 1036 C.

Therefore, using the first equation you provided (E = KQ/r^2), the correct solution would be:

E = (8.99x10^9)(1036 C)/(4x10^-6m)^2
E = 2.328x10^18 N/C

This matches with the first solution you provided, so it seems like you may have made a mistake in your calculations.

I hope this helps! If you have any further questions, please let me know.