The drawing shows a square, each side of which has a length of L = 0.25 m. Two different positive charges q1 and q2 are fixed at the corners of the square. Find the electric potential energy of a third charge q3 = -5 x 10-9 C placed at corner A and then at corner B. q1= 1.5e-9 and q2=4.0e-9

Without the figure, I have no idea which of the four cormers have q1 and q2 on them, nor where corners A and C are.

To find the electric potential energy of a third charge q3 placed at corner A and then at corner B, we need to calculate the electric potential energy due to the interaction between q3 and q1 and also between q3 and q2 separately.

The electric potential energy between two point charges q1 and q2 can be calculated using the formula:

U = (k * q1 * q2) / r

Where U is the electric potential energy, k is the electrostatic constant (k = 9 × 10^9 Nm^2/C^2), q1 and q2 are the charges, and r is the distance between the charges.

Let's first calculate the electric potential energy when q3 is placed at corner A:

1. Calculate the distance between q3 and q1. Since the square is symmetric, we can see that the distance is equal to the length of the side of the square (L).

2. Substitute the values into the formula:

U1 = (k * q1 * q3) / L

Now let's calculate the electric potential energy when q3 is placed at corner B:

1. Calculate the distance between q3 and q2. Since the square is symmetric, we can see that the distance is equal to the length of the diagonal of the square (L√2).

2. Substitute the values into the formula:

U2 = (k * q2 * q3) / (L√2)

To get the total electric potential energy when q3 is placed at corner A or corner B, we need to add the electric potential energies calculated in step 2 for each case:

Total electric potential energy at corner A = U1
Total electric potential energy at corner B = U2

Substitute the given values into the calculations, remembering to use the correct units, and you will find the electric potential energy at each corner.