Answer:
A.The positive z-direction
Explanation:
We are given that
Linear charge density of long line which is located on the x-axis=
Linear charge density of another long line which is located on the y-axis=
We have to find the direction of electric field at z=a on the positive z-axis if and
are positive.
The direction of electric field at z=a on the positive z-axis is positive z-direction .
Because and
are positive and the electric field is applied away from the positive charge.
Hence, option A is true.
A.The positive z-direction