If one lamp connects between two phases it, will it glow or not?

     If the voltage between the two phases is equal to the lamp voltage, then the lamp will glow. When the voltage difference is big it will damage the lamp and when the difference is smaller the lamp will glow depending on the type of lamp. But if both phases have the same voltage, then the voltage between the two phases is zero hence bulb will not glow.

     It's depending upon the phase difference between those phases in which you connect that lamp. If the phase difference is there, then the lamp is definitely glowing but if the phase difference is zero then the lamb won't glow (provided the magnitude of both phases must be the same). If you connect this lamp to our 3-phase system, then it will definitely glow because there is always a phase difference of 120 degrees and the magnitude is the same in our practical system.