what do you meean by amplitude of electric and magnetic field?

Electromagnetic wave is oscillating electric and magnetic fields, perpendicular to each other.

Amplitude is the maximum displacement of the particle of the medium (through which wave propogates) from the mean position.  But in electromagnetic wave it's the maximum values of strength of electric field and magnetic field in the oscillations of electric and magnetic field.

Since electric field is measured in N/C, the amplitude of electric field will have the units of N/C. The two amplitudes are related to each other.

regards,

Team,

TopperLearning