General Science Jis Sidhhant Par Optical Fibre Kaam Karta Hai , Wah Hai ?

जिस सिद्धान्त पर ऑप्टिकल फाइबर काम करता है , वह है ? - What is the principle on which optical fiber works? - Jis Sidhhant Par Optical Fibre Kaam Karta Hai , Wah Hai ? General Science in hindi,  Physics Apvartan question answers in hindi pdf  Prakeernan questions in hindi, Know About Purnn Aantarik Paravartan General Science online test General Science notes in hindi quiz book    Vyatikaran