Question

Which of the following options explains the process of ‘sputtering’ that occurs in Hollow Cathode Lamp?

(a) Positive ions collide with cathode surface and metal atoms from cathode are ejected

(b) Negative ions collide with cathode surface and metal atoms from anode are ejected

(c) Positive ions collide with negative ions and metal atoms from anode are ejected

(d) Positive ions collide with negative ions and photons are ejected

This question was posed to me in examination.

The question is from Atomic Absorption Spectroscopy topic in portion Colorimetry and Spectrometry of Analytical Instrumentation

Answer 1

Right answer is (a) Positive ions collide with cathode surface and metal atoms from cathode are ejected

To explain: When potential is applied across the electrode, the gas filled in tube ionises and flow of current occurs. Positive ions collide with negatively charged cathode surface and metal atoms from a cathode are ejected.