Thread: Deriving a formula for magnetic

Hello, it says that we must derive m = qB^2r^2/2V ..(volts)
using formula for kinetic energy and E= kq/r^2

thanks in advance for the help

Originally Posted by joeblack437

Hello, it says that we must derive m = qB^2r^2/2V ..(volts)
using formula for kinetic energy and E= kq/r^2

thanks in advance for the help

I can't make sense of your question. Is the charge in a magnetic field? Electric field? Both? What sort of fields? Constant?

Give all the of the question.

A mass spectometer accelerates ions through a voltage, V, before the ions enter a uniform magnetic field, B, that makes them turn. Develop the forumla m= qB^2r^2/2V for the mass of the ion, using kinetic and charge energy. the radius of the turn is r and the charge is q

Originally Posted by joeblack437

A mass spectometer accelerates ions through a voltage, V, before the ions enter a uniform magnetic field, B, that makes them turn. Develop the forumla m= qB^2r^2/2V for the mass of the ion, using kinetic and charge energy. the radius of the turn is r and the charge is q

K.E. = qV when ion enters magnetic field:

.... (1)

In magnetic field:

.... (2)

Substitute (2) into (1):

and I'm sure you can make m the subject and simplify.