ध्वनि के स्त्रोत व परावर्ती सतह के बीच न्यूनतम कितनी दूरी होनी चाहिए जिससे किस प्रति ध्वनि स्पष्ट रुप से सुनाई दे सके ? - What should be the minimum distance between the source of the sound and the reflecting surface so that the sound can be heard clearly against whom? - Dhwani Ke Source Wa paravarti Satah Ke Beech Minimum Kitni Doori Honi Chahiye Jisse Kis Prati Dhwani Spashta roop Se Sunayi De Sake ? General Science in hindi, Physics 17 Meeter question answers in hindi pdf 24 Meeter questions in hindi, Know About 10 Meeter General Science online test General Science notes in hindi quiz book 30 Meeter