Answer:
The electron's speed is 34007.35 m/s
Explanation:
It is given that,
Magnetic field, B = 0.34 T
Magnetic force on the electron, 
The electron follows a helical path. We have to find the speed of an electron. The formula for magnetic force is given by :

q = charge on an electron, 
v = velocity of an electron


v = 34007.35 m/s
Hence, this is the required solution.
To solve this problem we will apply the concept related to the magnetic dipole moment that is defined as the product between the current and the object area. In our case we have the radius so we will get the area, which would be



Once the area is obtained, it is possible to calculate the magnetic dipole moment considering the previously given definition:



Therefore the magnetic dipole moment is 
Answer:
i have absolutly no idea how to do it but i looked it up and your answer should be B. i could be wrong but thats what the web told me