Answer:
0.83x10^-9 T
Direction is towards +z axis.
Step-by-step explanation:
E = cB
E = magnitude of electrical 0.25 Em
c = speed of light in a vacuum 3x10^8 m/s
Therefore,
B = E/c = 0.25 รท 3x10^8
B = 0.83x10^-9 T
Magnetic fueld of a EM wave acts perpendicularly to its electric field, therefore it's direction is towards the +Z axis