# MAGNETIC FORCE

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here's the question, is my concept correct? the ans is 9.86 cm, but my ans is 13 cm, can anyone tell me which part is wrong?

perpendicular velocity is v sin tetha, so i sub all the values to the working above, i would get r=(mv)/(Bq sin 60) , where m=9.1x10^-31 , v= 4.0x10^7 ms^-1 B=2.0x10^-3 T , q=1.6X10^-9C , i would get 0.13m but not 9.86 cm.... what's wrong with my working?