Electric Field and point charges problem

In summary, an electric field is a physical quantity that describes the influence of an electric charge on other charges in its vicinity. It can be calculated for a point charge by dividing the electrostatic force exerted by the charge on a test charge placed at that point by the magnitude of the test charge. For a positive point charge, the electric field is directed radially outward from the charge. The magnitude of the electric field decreases with distance from the point charge, following an inverse square law. The superposition principle allows for the calculation of electric fields in more complex situations by considering the vector sum of individual electric fields caused by each point charge.
  • #1
Roshio6969
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A point charge q_1=-4.00\;{\rm nC} is at the point x = 0.600 m, y = 0.800 m, and a second point charge q_2=+6.00\;{\rm nC} is at the point x = 0.600 m, y = 0.

Calculate the magnitude of the net electric field at the origin due to these two point charges.
 
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  • #2
What have you done? Start setting up the vectors.
 
  • #3


The magnitude of the net electric field at the origin due to these two point charges can be calculated using the formula E = kq/r^2, where k is the Coulomb's constant, q is the charge of the point charge, and r is the distance from the point charge to the origin.

For point charge q_1 at (0.600 m, 0.800 m), the distance to the origin is r_1 = √(0.600^2 + 0.800^2) = 1.000 m.

For point charge q_2 at (0.600 m, 0), the distance to the origin is r_2 = √(0.600^2 + 0^2) = 0.600 m.

Substituting the values into the formula, we get:

E_1 = (9.0 x 10^9 Nm^2/C^2)(-4.00 x 10^-9 C)/(1.000 m)^2 = -36.0 N/C

E_2 = (9.0 x 10^9 Nm^2/C^2)(6.00 x 10^-9 C)/(0.600 m)^2 = 150.0 N/C

The net electric field at the origin will be the vector sum of E_1 and E_2, which can be calculated using the Pythagorean theorem:

E_net = √(E_1^2 + E_2^2) = √((-36.0 N/C)^2 + (150.0 N/C)^2) = 156.0 N/C

Therefore, the magnitude of the net electric field at the origin due to these two point charges is 156.0 N/C. This result shows that the electric field at the origin is directed towards the positive charge q_2, as expected since opposite charges attract each other.
 

1. What is an electric field?

An electric field is a physical quantity that describes the influence of an electric charge on other charges in its vicinity. It represents the force per unit charge that a test charge would experience if placed in the field.

2. How is the electric field calculated for a point charge?

The electric field at a point in space caused by a point charge is calculated by dividing the electrostatic force exerted by the charge on a test charge placed at that point by the magnitude of the test charge.

3. What is the direction of the electric field for a positive point charge?

The electric field for a positive point charge is directed radially outward from the charge, meaning it points away from the charge in all directions.

4. How does the magnitude of the electric field change with distance from a point charge?

The magnitude of the electric field decreases with distance from a point charge. It follows an inverse square law, meaning it decreases by a factor of four as the distance from the charge doubles.

5. What is the superposition principle in relation to electric fields?

The superposition principle states that the electric field at any point caused by multiple point charges is equal to the vector sum of the individual electric fields at that point caused by each individual charge. This principle allows for the calculation of electric fields in more complex situations.

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