Question

NMR, the value of alkynyl proton is less than the value of alkenyl proton.

Answer 1

NMR is a research technique that exploits the magnetic properties of certain atomic nuclei it determines the physical and chemical properties of atoms and molecules in which they are contained.
Unlike alkenyl hydrogens, alkynyl hydrogens give rise to shielded hydrogens or relatively high field chemical shifts from H-NMR when subjected to external magnetic field. This can be explained by cylindrical pi cloud around carbon carbon triple bond. Long range coupling is also observed in alkynes.
Also alkenyl hydrogen create external magnetic field that is perpendicular to double bond axis and causes electron in pi bond to rotate in circular path. The circular path of pi bond reinforce the external field where hydrogen are located thus bieng strongly deshielded and appearing low field in NMR spectrum.

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Answer 2

Yes, the NMR value of alkynyl proton is less than the value of alkenyl proton it is because of the movement of pi bond electrons in alkenyl hydrogens which make them unshielded. Alkenyl hydrogens forms an outer magnetic field which gives circular motion to pi bond electrons and this circular motion makes external magnetic field more stronger. Thus this results into the low field in NMR spectrum.