what evidence showed that the particles in the beam of crookes' tube were negatively charged?

Answer 1

Hi:

There was two way they prove this :

# 1 when the steam of electron flowing from one end of the tube toward the other. they put a horse shoe shape magnet with the poles beside the beam and obversed which way the beam was deflected and it went right after leaving the magnet saying it had a negative charge and when the poles of the magnet were reversed the beam went left after leaving the manget thus proving it was negative

#2) they put two plates in the Cooke's tube added both positive and negative charges and the beam went toward the positive charge plate and away from the negative charge plate and when the plate charges where reversed the electron beam went toward the positive charged plate and away from the negative charge plate Thus proving the particles in the beam where negatively charged. because alike charges repell one another and unlike charge attract one another ( basic electric law of charges)

Thus proving the the particle were negativity charge this the bases for all vacuum tubes and T.V. and oscilloscopes and led to atomic energy and research

Answer 2

They probably ran the tube through a loop with a negative or positive charge, then observed the effect on the particles in the beam.