Light emission from electronic transitions in an oxygen atom occurs when an electron moves from a higher energy level to a lower energy level, releasing energy in the form of a photon. Among possible electronic transitions in the oxygen atom:

• Transitions such as n=3→n=2n=3\to n=2n=3→n=2 and n=1→n=2n=1\to n=2n=1→n=2 will result in light emission because these involve an electron dropping to a lower energy level.
• Transitions like n=1→n=3n=1\to n=3n=1→n=3 or n=2→n=3n=2\to n=3n=2→n=3 are electron absorptions (moving to a higher energy level) and thus do not emit light.

Therefore, the electronic transitions in oxygen atom that will result in light emission are those where an electron moves from a higher to a lower principal quantum number, such as:

• n=3→n=2n=3\to n=2n=3→n=2
• n=1→n=2n=1\to n=2n=1→n=2

This is consistent with the principles of atomic electron transitions and photon emission.