1)

The kinetic energy of an electron in the second Bohr orbit of a hydrogen atom is [a0, is Bohr radius]


A) h24π2ma20

B) h216π2ma20

C) h232π2ma20

D) h264π2ma20

Answer:

Option C

Explanation:

According to Bohr's model

  mvr=nh2π|

    (mv)2=n2h24π2r2

KE=12mv2=n2h28π2r2m......(i)

Also Bohr's radius for  H-atom is r=n2a0

Substiuting 'r' in equation (i) gives

 KE=h28π2n2a20m

wher n=2,

  KE=h232π2ma20