[填空题]
A proton follows a spiral path through a gasgjhh9vwe ;j () indcrfykg36 su o2 ai8)dy, *1mr a magnetic field of 0.010 T, perpendicular to the plane of the spiral, as shown in (Fig. Below). In two successive l uf*3dak )yogycsd2m16 ir8, roops, at points P and Q, the radii are 10.0 mm and 8.5 mm, respectively. Calculate the change in the kinetic energy of the proton as it travels from P to Q. $ \times10^{-20 }\;J$
