In a certain region of space, the magnetic flux density B B\,B is approximately 50 μT50\ \mu\text{T}50 μT.
What is the magnitude of the force on a proton with velocity v=250 km s−1v = 250\ \text{km s}^{-1}v=250 km s−1 as it is moving perpendicular to this magnetic field? (The charge of a proton is 1.6 × 10-19 C)
2.0×10−24 N2.0 \times 10^{-24}\ \text{N}2.0×10−24 N
2.0×10−21 N2.0 \times 10^{-21}\ \text{N}2.0×10−21 N
2.0×10−18 N2.0 \times 10^{-18}\ \text{N}2.0×10−18 N
2.0×10−15 N2.0 \times 10^{-15}\ \text{N}2.0×10−15 N
