QUESTION 12 A proton enters a uniform magnetic field at a 90 -degree angle. Considering the proton's motion in the magnetic field, the magnetic force serves as the
◻
A. gravitational force B. tension C. centripetal force D. frictional force
q,
QUESTION 13 In the previous question, the proton's speed is
3.51\times 10^(3)(m)/(s)
, and the uniform magnetic field has a strength of
0.049T
, the radius of the proton's path is
◻
m. Exponent format with
3SF
.