A unifrom magnetic field `B` is acting from south to north and is of magntitdue `1.5 Wb//m^(2)`. If a proton having mass `= 1.7xx10^(-27) kg` and charge `= 1.6xx10^(-19) C` moves in this field vertically downwards with energy `5 MeV`, then the force acting on it will be

Options

A. `7.4xx10^(12)N`
B. `7.4xx10^(-12)N`
C. `7.4xx10^(19)N`
D. `7.4xx10^(-19)N`

Answer

2

Explanation

`F=Bqv` and `KE=(1)/(2)mv^(2)impliesF=qBsqrt((2KE)/(m))`