Point Charges Homework/Studying help

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To find the point along the line joining two positive point charges, q1 (0.50 x 10^-9 C) and q2 (8.00 x 10^-9 C), where the total electric field is zero, the principle of superposition is applied. The electric fields created by both charges repel, and the direction of these fields must be considered. Using Coulomb's law, the magnitudes of the electric fields due to each charge are calculated, with E1 from q1 being 3.12 x 10^-4 N/C and E2 from q2 being -3.12 x 10^-3 N/C. The total electric field is then determined by subtracting the magnitudes of these fields, leading to the conclusion that the two fields can balance at a specific point between the charges. The calculations demonstrate the importance of understanding electric field interactions in determining equilibrium points.
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Heres another similar question:

Two point charges, q1= 0.50 x 10^-9 C and q2= 8.00 x 10^-9 C are seperayed by a distance of 1.20 m. At what point along the line joining the points charges, is the total electric field die to the two charges equal to zero?
 
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Can you find a distance r between the two charges where the magnitude of each field is equal?

Hint: Since the charges are both positive the fields both repel.
 


To find the point where the total electric field is equal to zero, we can use the principle of superposition, which states that the electric field at a point due to multiple point charges is equal to the vector sum of the individual electric fields at that point.

First, we need to determine the direction of the electric fields at the point in question. We know that electric fields point away from positive charges and towards negative charges. In this case, q1 is positive and q2 is negative, so the electric fields will be pointing in opposite directions.

Next, we can use Coulomb's law to find the magnitude of the electric fields at the point. Coulomb's law states that the electric field at a point due to a point charge is directly proportional to the magnitude of the charge and inversely proportional to the square of the distance between the point charge and the point in question.

In this case, we have two point charges, so we need to find the electric field due to each charge separately and then add them together. The equation for the electric field due to a point charge is E = kq/r^2, where k is the Coulomb's constant (8.99 x 10^9 Nm^2/C^2), q is the magnitude of the charge, and r is the distance between the charge and the point in question.

For q1, the distance is 1.20m, so the electric field would be E1 = (8.99 x 10^9 Nm^2/C^2)(0.50 x 10^-9 C)/(1.20m)^2 = 3.12 x 10^-4 N/C.

For q2, the distance is also 1.20m, but the charge is negative, so the electric field would be E2 = (8.99 x 10^9 Nm^2/C^2)(-8.00 x 10^-9 C)/(1.20m)^2 = -3.12 x 10^-3 N/C.

Now, we can add these two electric fields together to find the total electric field at the point. Since the fields are pointing in opposite directions, we can subtract the magnitudes to find the net electric field.

Etot = |E1| - |E2| = (3.12 x 10^-4 N/C) - (3.12 x 10^-3 N/C) =
 
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