Explanation:
ummm I believe it's frequency
Answer:
The zero field location has to be on the line running between the two point charges because that's the only place where the field vectors could point in exactly opposite directions. It can't be between the two opposite charges because there the field vectors from both charges point toward the negative charge.
The answer to this question would be a transverse wave, because the vibration travels parallel to the direction that the wave is traveling.
Answer:
Positive z direction.
Explanation:
The magnetic force acting on the electron is given by the formula as :

q is the charge on proton
v is the speed of proton
B is the magnetic field
It is mentioned that the proton is moving with a velocity in the positive x-direction. The uniform magnetic field B in the positive y-direction such taht,
q = +e
v = vi
B = Bj

Since, 

So, the magnetic force acting on the proton in positive z axis. Hence, the correct option is (d) "positive z direction".