Cathode Ray Tube - Canal Rays

Purpose

Demonstrate canal rays present in a cathode ray tube.

Equipment

Canal ray tube, power supply, bar magnet.◙

Suggestions

Best for individual viewing.◙

Setup Time

5 min.

Images

p3-22

Description

Perforations in the cathode of the tube permit positive ions to pass through the cathode, forming "canal rays" or "positive rays." The effect of a magnet on these rays may be compared with its effect on electrons moving in the opposite direction as in demonstration K1-12: CATHODE RAY TUBE - DEFLECTION BY MAGNET. The deflections of the beam are visible if viewed closely with very low ambient light level.