In mass spectrometer used for measuring the masses of ions, the ions are initaily accerlerated by an electric potential `V` and then made to describe semicircular paths of radius `R` using a magnetic field `B`.if `V` and `B` are kept constant, the ratio `(("charg e on the ion")/("mass of the ion"))` will be propertional to:

Options

A. `1/R^(2)`
B. `R^(2)`
C. R
D. `1/R`

Answer

a

Explanation

In electrostatic, `qV = 1/2 mv^(2) rArr v = sqrt((2qV)/m)`
When charge particle having velocity v in magnetic field ,
`qvB = (mu^(2))/R rArr qB = (mv)/R = m/R sqrt((2qV)/m) `
`sqrt(q/m) = 1/(RB) sqrt(2V)`
`rArr q/m propto 1/R^(2) `