Which electric and magnetic field orientations of electromagnetic(em) waves describe a wave traveling along the positive x-axis?

What is the earliest point in the universe that we can observe? why can’t we see back further than this?

Photons with the highest energy have the longest period

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.