Which way does the electric field go in this question?

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Homework Statement



Find the electric field midway between a -3.0nC charge and a -5.0 nC charge that are separated by 0.60 m.

Homework Equations



ε= kq/r2

The Attempt at a Solution



net ε = ε1 + 2

I drew my -3.0 charge on the left and my -5.0 charge on the right

midway in between is 0.3 m

they are both negative charges, so the fields lines are towards each charge (away from the centre) and the -5.0 charge has more lines, because it has the bigger charge

so I solved for ε 1 and got -300 N/C
I solved for ε 2 and got -500 N/C

I think that ε 1 should be subtracted from ε 2 so the result is

-200 N/C

The field overall, I think should point toward the larger negative charge

it should point toward the -5.0 nC charge, in my drawing, to the RIGHT.

is that correct?

Thanks!
 
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Answers and Replies

  • #2
SammyS
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Homework Statement



Find the electric field midway between a -3.0nC charge and a -5.0 nC charge that are separated by 0.60 m.

Homework Equations



ε= kq/r2

The Attempt at a Solution



net ε = ε1 + ε2

I drew my -3.0 charge on the left and my -5.0 charge on the right

midway in between is 0.3 m

they are both negative charges, so the fields lines are towards each charge (away from the centre) and the -5.0 charge has more lines, because it has the bigger charge

so I solved for ε 1 and got -300 N/C
I solved for ε 2 and got -500 N/C

I think that ε 1 should be subtracted from ε 2 so the result is

-200 N/C

The field overall, I think should point toward the larger negative charge

it should point toward the -5.0 nC charge, in my drawing, to the left.

is that correct?

Thanks!
Yes, the field at the midpoint, points toward the -5.0 nC charge.
 

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