विद्युत धारा का चुम्बकीय प्रभाव सर्वप्रथम अवलोकन किया गया ? - The magnetic effect of electric current was first observed in? - Vidyut Dhara Ka Chumabakiya Prabhav Sarwapratham Avalokan Kiya Gaya ? General Science in hindi, वैज्ञानिक और उनके अविष्कार orastade Dwara question answers in hindi pdf Ferade Dwara questions in hindi, Know About Henry Dwara General Science online test General Science notes in hindi quiz book volta Dwara