Answer: The released electromagnetic wave will travel in +y direction
Explanation:
It should be noted that, in a situation, whereby an excited hydrogen atom releases an electromagnetic wave to return to its normal state. And it's also evident that the futuristic dual electric/magnetic field tester on the electromagnetic wave to find the directions of the electric field and magnetic field is used. Eventually, your device tells you that the electric field is pointing in the positive y direction and the magnetic field is pointing in the positive x direction. Therefore, the released electromagnetic wave will travel in +y direction.