Alpha Particles, Each Having a Charge Of $+ 2 e$ And a Mass Of

question 31

Multiple Choice

Alpha particles, each having a charge of $+ 2 e$ and a mass of $6.64 \times 10 ^ { - 27 } \mathrm {~kg}$ , are accelerated in a uniform $0.80$ -T magnetic field to a final orbit radius of $0.30 \mathrm {~m}$ . The field is perpendicular to the velocity of the particles. How long does it take an alpha particle to make one complete circle in the final orbit? $\left( e = 1.60 \times 10 ^ { - 19 } \mathrm { C } \right)$

• A) \(0.49 \mu \mathrm { s }\)
• B) \(0.40 \mu \mathrm { s }\)
• C) \(0.15 \mu \mathrm { s }\)
• D) \(0.33 \mu \mathrm { s }\)
• E) \(0.25 \mu \mathrm { s }\)