Question

In a mass spectrometer used for measuring the masses of ions, the ions are initially accelerated 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 (change on the iron/ mass of the ion) will be proportional to

(a) 1/R² 

(b) R²

(c) R

(d) 1/R

Answer 1

The correct option is (a) 1/R² .

Explanation:

In mass spectrometer when ions are accelerated through potential V,

where m is the mass of ion, q is the charge of the ion.

As the magnetic field curves the path of the ions in a semicircular orbit