Question

In the Bainbridge mass spectrometer, the magnetic field magnitude in the velocity selector is 0.650 T, and ions having speed of 1.82 x 10⁶ m/s pass through undeflected.

(A) What is the electric field magnitude in the velocity selector; and

(B) If the separation of the plates is 5.20 mm, what is the potential difference between plates P and P^x?

Answer 1

Relation between electric field and magnetic field is given by:

from force balance

Fe = Fm

q*E = q*v*B

E = v*B

E = 1.82*10^6 m/sec*0.650 T

E = 1.183*10^6 V/m

Part B

We know that

E = V/d

Using known values:

V = E*d

V = 1.183*10^6*(5.2*10^-3)

V = 6151.6 V