Answer to Question 5

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(a) Energy of the particle = 5.45 106 eV 1.60 10-19 J eV-1 = 8.73 10-13 J

      Speed of alpha particle:

      v2 = (2 8.73 10-13 J) 6.64 10-27 kg = 2.627 1014 m2 s-2

      v = (2.627 1014 m2 s-2)0.5 = 1.62 107 m s-1

 

(b)  Radius:

       r = mv/Bq = (6.64 10-27 kg 1.62 107 m s-1) (0.86 T 2 1.60 10-19 C)

       r = 0.7821 m = 0.78 m (2 s.f.)

 

(c)  Use Fleming's Left Hand Rule:

       The direction is upwards.