Current `I_1 and I_2` flow in the wires shown in Fig. The field is zero at distance x to the right of O. Then

Options

A. `x=((I_1)/(I_2))a`
B. `x=((I_2)/(I_1))a`
C. `x=((I_1-I_2)/(I_1+I_2))a`
D. `x=((I_1+I_2)/(I_1-I_2))a`

Answer

C

Explanation

(c) `(mu_0I_1)/(40pi(a+x))=(mu_0I_1)/(40pi(a-x))`
`(a-x)/(a+x)=(I_2)/(I_1) implies x=((I_1-I_2)/(I_1+I_2))a`