Which one of the following statements is not true for cathode

1. Cathode rays produce heat when incident on metals
2. Cathode rays travel in a straight line
3. Cathode rays do not deflect in electric field
4. Cathode rays produce fluorescence when they fall on certain meterials

Cathode rays are negatively charged rays. Hence, when electric field is applied to them, then they deflect in direction opposite to electric field.