Four point charges qA = 2 µC, qB = −5 µC, qC = 2 µC, and qD = −5 µC are located at the corners of a square ABCD of side 10 cm.

Question 6:

Four point charges q_A = 2 µC, q_B = −5 µC, q_C = 2 µC, and q_D = −5 µC are located at the corners of a square ABCD of side 10 cm. What is the force on a charge of 1 µC placed at the centre of the square?

Solution:

in this problem  Four point charges q_A = 2 µC, q_B = −5 µC, q_C = 2 µC, and q_D = −5 µC are located at the corners of a square ABCD of side 10 cm.

Given that

 A square ABCD  with each side = 10 cm  = 0.1 m (divide by 100 to convert cm to m )

Charge q_A = 2 µC, q_B = −5 µC, q_C = 2 µC, and q_D = −5

And 1 µC placed at the centre of the square

Draw the figure

 

Apply Coulomb’s law

q₁ = first charge

q₂ = Second charge

r = distance between both charge

ε₀= permittivity of free space

From the figure

We know that OA = OC hence  

F_OA = - F_OC

F_OA + F_OC  = 0

Similarly  

F_OB + F_ODC  = 0

Similarly other forces will also cancel out to each other

F_TOTAL =0

Hence sum of all forces will =0