Question

4 equal charge placed at the corner of square.find electric potential​

Answer 1

Electric potential due to a system of charges placed in air is given by

V = V_1 + V_2 + V_3 + ... + V_n

= 1/(4piepsi_0)sum_(i=1)^nq_i/r_i    

= 1/(4piepsi_0)(q_1/r_1 + q_2/r_2 + q_3/r_3 + ... +q_n/r_n)

Here, four charges have been placed at the corners of a 20 cm square. The electric potential at the center of the square has to be calculated.

the distance of the charges from the centre of the square, r should be equal to 1/2 the length of the diagonal.

r=1/2*20sqrt2 = 10sqrt2 cm =10sqrt2*10^-2 m

Therefore, V = 1/(4pi*(8.854*10^-12)*10sqrt2*10^-2)(10 + (-5) + (-15) + 20)*10^-6 Volts

= 10*10^-6/(4pi*(8.854*10^-12)*10sqrt2*10^-2) Volts

= 6.355*10^5  Volts

Therefore, the electric potential at the centre of the square will be 6.355*10^5 Volts.