In a photographic emulsion the track of a proton moving perpendicular to a magnetic field of 0.60T is observed to be a circular arc of radius 1.2cm. What is the kinetic energy of the proton in electronvolts?​

luster is not a good characteristic to use by itself because luster is the property of minerals that indicates how much the surface of a mineral reflects light. the luster of a mineral is affected by the brilliance of the light used to observe the mineral surface.

this would be about 43%

t = 1/400 h   ⇔ 0.0025 h ⇔ 9s ⇔ 0.15 m

any of the answers are correct.