There's a problem my professor assigned, but I'm not sure which equation/process I should use to solve it. Please help.

Two particles having charges of 0.420nC and 15.1nC are separated by a distance of 1.50m. At what point along the line (in m from the particle with .420nC charge) connecting the two charges is the net electric field due to the two charges equal to zero? Also, Where would the net electric field be zero if one of the charges were negative? (answer as a distance from the charge initially equal 0.420nC)

It is rather simple. Draw the diagram,

a) let x be the distance from one charge, 1.5-x the distance from the other charge. Now, figure E

E=kq/r^2

Now notice that E on each charge is away from the charge. So they are oppositely directed.

then kq1/(r1^2)^2= kq2/(r2)^2

solve for x.

Now on the second part, the x will be outside the line joining them. Do it the same way.

To solve this problem, we need to use the concept of electric fields and the principle of superposition. The electric field is a vector quantity that represents the force experienced by a positive test charge at a given point in the presence of other charges.

1. Start by understanding the principle of superposition: The net electric field at a point in space due to multiple charges is the vector sum of the individual electric fields created by each charge.

2. Calculate the electric field created by each charge at a given point using Coulomb's Law:

Electric field due to a point charge (E) = (k * Q) / r^2

Where:
- k is Coulomb's constant (8.99 x 10^9 N m^2/C^2)
- Q is the charge of the particle creating the field
- r is the distance between the charge and the point at which we want to find the electric field

3. Subtract or add the electric fields depending on the charges' signs: Since electric fields are vector quantities, they can either add or cancel each other out depending on the direction and magnitude.

Now, let's solve the problem step by step:

For the first part of the problem, where both charges are positive:
1. Calculate the electric field due to the first charge at a distance x from the charge with 0.420nC charge.
2. Calculate the electric field due to the second charge at the same distance x.
3. These two electric fields must add up to zero since the net electric field is zero, so set up the equation:
E1 + E2 = 0
(k * Q1) / (x^2) + (k * Q2) / ((1.50 - x)^2) = 0
Substitute the known values: Q1 = 0.420nC, Q2 = 15.1nC, x is the unknown distance.
4. Solve the equation to find the value of x, which corresponds to the distance from the charge initially with the 0.420nC charge to the location where the net electric field is zero.

For the second part of the problem, where one of the charges is negative:
1. Follow the same steps as above.
2. However, during step 2, while calculating the electric field due to the second charge, consider the negative sign of the charge.
3. Set up the equation as follows:
E1 - E2 = 0
(k * Q1) / (x^2) - (k * Q2) / ((1.50 - x)^2) = 0
Substitute the known values, with Q1 = 0.420nC, Q2 = -15.1nC, and solve to find the value of x, which represents the distance from the charge initially with the 0.420nC charge to the location where the net electric field is zero.

By following these steps and the equations provided, you should be able to solve the problem and find the distances where the net electric fields are zero.