87 . In an experiment similar to the one conducted by J.J. Thomson to measure the specific charge of the electron, a beam of electrons enters, in a direction parallel to the plates, into a capacitor whose plates are 5.40 cm apart and between which a potential difference of 1.45 kV is applied.

The electrons travel through an electric field region of length x = 10.0 cm and, when only the electric force is present, are deviated by y = 2.00 cm in the direction perpendicular to the plates.

The magnetic field generates on the electrons a force opposite to the electric one, which is 7.72 104 T.

The action of the magnetic field compensates for the effect of the electric field.

Calculate, based on this data, the value of the specific charge of the electron [result is [1,80 10¹¹C/kg]]