An `alpha` - particle with (e/m) ratio 4.8 x 10-11CKg-1 travels in a circular path of radius 0.45 m in a magnetic field of 1.2 T, then the speed of the `alpha` - particle is
2.6 x 104m/s
2.6 x 105m/s
2.6 x 106m/s
1.3 x 107m/s
please check this question
e/m can't be equal to 4.8X10^-11