A charged particle, passing through a certain region of space, has a velocity whose magnitude and direction remain constant.

(a) If it is known that the external magnetic field is zero everywhere in this region, can you conclude that the external electric field is also zero?

Explain.

(b) If it is known that the external electric field is zero everywhere, can you conclude that the external magnetic field is also zero?

Explain.

2 answers

I will be happy to critique your thinking. It is not nice to post a lot of questions with each a different name. Usually, slackers or answer moochers do that.
I am sorry but you are mistaken. This is the first time I have been on this website in about 3 weeks. I have posted the question just above this one as well and another one just a minute ago for you to check my working. I will make an educated guess and repost the question.