Q.

Speed of an electron in Bohr's 7th orbit for Hydrogen atom is 3.6×106 m/s. The corresponding speed of the electron in 3rd orbit, in m/s is             [2023]

1 1.8×106  
2 7.5×106  
3 3.6×106  
4 8.4×106  

Ans.

(4)

VnZn

z=1

 Vn1n

 V3V7=73

 V3=73V7=73×3.6×106 m/s=8.4×106 m/s