<Li> <P> When the magnet is reversed, it bends the rays down, so the shadow is lower . The pink glow is caused by cathode rays striking residual gas atoms in the tube . </P> </Li> <P> When the magnet is reversed, it bends the rays down, so the shadow is lower . The pink glow is caused by cathode rays striking residual gas atoms in the tube . </P> <P> After the 1654 invention of the vacuum pump by Otto von Guericke, physicists began to experiment with passing high voltage electricity through rarefied air . In 1705, it was noted that electrostatic generator sparks travel a longer distance through low pressure air than through atmospheric pressure air . </P> <P> In 1838, Michael Faraday passed a current through a rarefied air filled glass tube and noticed a strange light arc with its beginning at the cathode (negative electrode) and its end are at the anode (positive electrode). In 1857, German physicist and glassblower Heinrich Geissler sucked even more air out with an improved pump, to a pressure of around 10 atm and found that, instead of an arc, a glow filled the tube . The voltage applied between the two electrodes of the tubes, generated by an induction coil, was anywhere between a few kilovolts and 100 kV . These were called Geissler tubes, similar to today's neon signs . </P>

Magnitude of deflection of cathode rays in discharge tube is more when