Two 10 cm diameter charged rings face each other, 20 cm apart. The left ring is charged to -20 nC and the right ring is charged to +20 nC.
You have not said what the question is, but if you want the force between them, use Coulomb's Law.
Sorry
What is the force Fvec on a 1.2 nC charge placed at the midpoint?
To find the electric field at a point between two charged rings, given their charge and separation, you can use the principle of superposition.
First, let's find the electric field of each ring individually. The electric field due to a uniformly charged ring is given by the formula:
E = k * (Q / R^2)
Where:
E is the electric field at a point on the axis of the ring,
k is the electrostatic constant (9 x 10^9 N m^2/C^2),
Q is the charge of the ring, and
R is the distance from the center of the ring to the point.
For the left ring, which is negatively charged, Q = -20 nC = -20 x 10^(-9) C. The diameter of the ring is 10 cm, so the radius (R) is half of that, which is 5 cm or 0.05 m.
E_left = k * Q_left / R_left^2
E_left = (9 x 10^9 N m^2/C^2) * (-20 x 10^(-9) C) / (0.05 m)^2
Calculating this expression will give you the electric field due to the left ring.
For the right ring, the charge (Q) is +20 nC = +20 x 10^(-9) C, and the radius (R) is the same as the left ring (0.05 m).
E_right = k * Q_right / R_right^2
E_right = (9 x 10^9 N m^2/C^2) * (+20 x 10^(-9) C) / (0.05 m)^2
Calculating this expression will give you the electric field due to the right ring.
Now, to find the electric field at a point between the two rings, we need to consider their superposition. The electric fields due to each ring add up since the electric field is a vector quantity.
E_total = E_left + E_right
Substituting the calculated values of E_left and E_right into this expression will give you the total electric field at the given point.
Please note that the signs of the individual electric fields need to be considered when adding them up. Also, when using the superposition principle, it is important to note the direction of the electric field vectors, as it may affect the final answer.