Data:
B=?, v=6.10*10^7 m/s, R=1.70m, m=1.67*10^(-27)kg, q=-1.6*10^(-19)C
Answer:
Firstly, we need to remember the formula for the Magnetic force, which is:

However, in this scenario the magnetic force will act as a centripetal force, thus:

If we equal both of them:

Replacing our values:

Then, our magnetic field will be B=0.3745T