However, you could describe it using Sanskrit words for its components and function:
* दीपक (deepak) - lamp, light
* नलिका (nalika) - tube
* विद्युत (vidyut) - electricity
Therefore, you could describe a tube light as: विद्युत नलिका दीपक (vidyut nalika deepak), which literally translates to "electric tube lamp."
This is a descriptive phrase rather than a single word, but it captures the essence of a tube light.