Large magnetic-field and microwave effects were detected on the spin-adduct yield in the photoreduction of 1,5-diphenyl-1,4-pentadiyn-3-one (I) and 1,3-diphenyl-2-propyn-1-one (II) in SDS micellar solution. These phenomena were interpreted with the "relaxation mechanism" for the intermediate radical pair. The dynamic behavior of the intermediate radical pair was elucidated by the pulse-mode product-yield-detected ESR (PYESR), in which the effect of microwave pulse on the spin adduct yield is observed. The rate constants for hydrogen abstraction, escape process of radical pair, and so on were successfully determined through the simulation of these microwave effects as functions of the delay period which is brought into the pulse sequences. The reactivity of excited ketones in the hydrogen abstraction increases significantly in the sequence I much greater than III > II, where III represents benzophenone studied as a reference system. The results were compared with those estimated from the transient absorption observations.