An alpha particle (He2+\text{He}^{2+}He2+) travels in a circular orbit of radius 1.25 m inside a magnetic confinement fusion device. The uniform magnetic field within the device has a flux density of 1.80 T1.80\text{ T}1.80 T.
What is the momentum of the alpha particle?
3.60×10−19 kg m s−13.60 \times 10^{-19}\text{ kg m s}^{-1}3.60×10−19 kg m s−1
4.61×10−19 kg m s−14.61 \times 10^{-19}\text{ kg m s}^{-1}4.61×10−19 kg m s−1
7.20×10−19 kg m s−17.20 \times 10^{-19}\text{ kg m s}^{-1}7.20×10−19 kg m s−1
1.44×10−18 kg m s−11.44 \times 10^{-18}\text{ kg m s}^{-1}1.44×10−18 kg m s−1
