Question

The charge per unit length of the four quadrant of the ring is 2λ,-2λ,λ and -λ respectively . the electric field at the centre is ​

Answer 1

Let the charges be denoted by C

and according to question

So    C1 = 2k
         C2 = -2k
         C3 = k
          C4 = -k

Total current in electric field   = C1 + C2 + C3 + C4
                                               = 2k - 2k + k - k
                                               = 0
thus   total electric current is zero