The research aims to develop and to assess alternative conceptions of second year’s Sundanese scholars on light wave with Multitier Open-ended Light Wave Instrument (MOLWI). The research method has been utilized by the 3D+1I model (Defining, Designing, Developing and Implementing). Participants who involved in this research are 26 of second year’s scholars (11 male students, namely “Ujang” and 15 female students, namely “Eneng”, the average age of them are about 17 years of Sundanese-tribe). The MOLWI consist of 15 questions which has been already analysed by Rasch analysis. Students' conceptions have ever been categorized regarding to the six categories, that are; Sound Understanding (SU), Partial Positive (PP), Partial Negative (PN), Misconception (MC), No Understanding (NU), and No Coding (NC). The research results show that the PN category has the highest percentage about 86 percent in the number six. The lowest category is the NC category about four percent in the number of 3, 5, 7 and 13. While Rasch analysis explains the Sundanese-scholars only answer confidently on easy questions and not misconceptions.