The statements that correctly compare the gravitational force with the electrical force are the following:
-The gravitational force can be attractive.
-The electrical force can be repulsive.
-The electrical force can be attractive.
-Any two objects experience a gravitational force between them.
Answer:
a
The direction of the wave propagation is the negative z -axis
b
The amplitude of electric and magnetic field are
,
respectively
Explanation:
According to right hand rule, your finger (direction of electric field) would be pointing in the positive x-axis i.e towards your right let your palms be face toward the direction of the magnetic field i.e negative y-axis (toward the ground ) Then anywhere your thumb stretched out is facing is the direction of propagation of the wave here in this case is the negative z -axis
The Intensity of the wave is mathematically represented as

Given that 
Making
the subject we have

Substituting values as given on the question
![E_{rms} = \sqrt{\frac{7.43 *10^7[\frac{W}{m^2} ]}{0.5 * 3.08*10^8 *8.85*10^{-12}} }](https://tex.z-dn.net/?f=E_%7Brms%7D%20%3D%20%5Csqrt%7B%5Cfrac%7B7.43%20%2A10%5E7%5B%5Cfrac%7BW%7D%7Bm%5E2%7D%20%5D%7D%7B0.5%20%2A%203.08%2A10%5E8%20%2A8.85%2A10%5E%7B-12%7D%7D%20%7D)

The amplitude of the electric field is mathematically represented as



The amplitude of the magnetic field is mathematically represented as

Substituting value

