three equal and similar charges each of 'q' units are placed at the corners of the square of side 'a' .find the electric field strength at the fourth corner?

E=kq/r^2 and in the direction of r.

Add these as vectors. If you are careful, you can use symmetry to simplify it.

Here is a similar question on the symmetry issue. http://www.jiskha.com/display.cgi?id=1270726327

3000mm=____m?

Can you please Explain and Show the answer ?

To find the electric field strength at the fourth corner of the square, we need to analyze the electric fields created by each of the three charges at that point. Here's how you can determine the electric field strength:

Step 1: Determine the electric field due to each charge
The electric field created by a point charge can be calculated using Coulomb's Law:

Electric field (E) = k * (q/r^2)

Where:
- E is the electric field
- k is Coulomb's constant (k = 9 x 10^9 Nm^2/C^2)
- q is the charge
- r is the distance between the charge and the point where you want to calculate the electric field

Step 2: Calculate the distance from each charge to the fourth corner
Since the charges are placed at the corners of a square, we can use the Pythagorean theorem to calculate the distance (r) between each charge and the fourth corner. The distance r will be equal to the diagonal of the square, which is √2 times the length of the side (a).

r = √2 * a

Step 3: Calculate the electric field due to each charge
Using the formula from Step 1 and the distance from Step 2, calculate the electric field created by each charge at the fourth corner.

E1 = k * (q/r^2) (for the top-left charge)
E2 = k * (q/r^2) (for the top-right charge)
E3 = k * (q/r^2) (for the bottom-left charge)

Step 4: Find the net electric field at the fourth corner
The electric field is a vector quantity, so to find the net electric field at the fourth corner, we need to consider the directions of the three electric fields. Since the charges have the same magnitude and are placed at the corners of a square, the electric fields will be of equal magnitude and will form angles of 45 degrees with each other.

Net Electric Field (E_net) = √[ (E1^2) + (E2^2) + (E3^2) + 2 * E1 * E2 * cos(45) ]

Step 5: Simplify the expression
Substitute the values of E1, E2, and E3 from Step 3 into the formula for E_net and simplify to get the final answer.

Once you have calculated the electric field strength at the fourth corner of the square, you will have your answer.