Question

How to find velocity of electron given bohr radius?

Answer 1

use BOHR's postulate :
1. angular momentum of electron in orbital is integral multiple of nh/2π .
e.g mvr = nh/2π

2. electrons and nucleus are held together by electrostatic force of attraction.
e.g mv²/r = Kze²/r²
mv² = Kze²/r

from (1)
r = nh/2πmv put in (2)

mv² = KZe²/nh/(2πmv)
mv² = KZe² × 2πmv/nh
v = 2πKZe²/nh
v = { 2πKZe²/h} (Z/n)

2πKZe²/h is constant Let A

v =A.(Z/n)
hence, finding of velocity of electron in nth orbit whose atomic no Z .
is V = A.( Z/n)