There is an electromagnetic wave traveling in the -z direction in a standard right-handed coordinate system. what is the direction of the electric field, e→ , if the magnetic field, b→ , is pointed in the +x direction?

The direction of the electric field, E→, is pointed in the +y direction.

Explanation:

One can use the right hand rule to illustrate the direction of travel of an electromagnetic and thereby get the directions of the electric field, magnetic field and direction of travel of the wave.

The right hand rule states that the direction of the thumb indicate the direction of travel of the electromagnetic wave (in this case the -z direction) and the curling of the fingers point in the direction of the magnetic field  B→ (in this case the +x direction), therefore, the electric field direction E→ is in the direction of the fingers which would be pointed towards the +y direction.

(75°f − 32) × 5/9 = 23.889°c