use
ANS_Probsound_extra1.doc
ANS_test51.doc
Ans_Probligth_extra1.doc
Probligth_55.docx
Probsound_53.docx
Probsound_55.docx
Probsound_59.docx
Probwave_53.doc
Probwave_57.docx
Probwave_59.docx
light_from irodov.docx
move_mirror.docx
optic_j2.docx
optic_prob with ans.docx
prob1.ppt
test51.doc
test52.doc
test55_with ans.docx
test56.docx