Question

9. The angular momentum of an electron in a given
orbit is J. Its kinetic energy will be:
a)j^2/ 2mr^2
b)jv/r
c)j^2/2m
d)2j​

Answer 1

△▼△▼ ђ๏ɭค❣ △▼△▼

according to Bohr

angular momentum of an electron = nh/2(pi)

hence,

mvr = nh/2(pi)

according to question angular momentum is “J”

means 

nh/2(pi) = J

now 

mvr = nh/2(pi)

squaring both sides

m2v2r2 = n2h2/4(pi)2

m2v2r2 = J2

now knietic energy = 1/2mv2

hence,

multiplying both sides my ½

1/2m2v2r2 = J2/2

1/2mv2 = J2/2r2m

⫷⫷⫷ คภรฬєг : a) J^2/ 2 r^2 m⫸⫸⫸

✧༺♥༻∞ ђ๏קє ย ɭเкє เՇ♥️ ˚*∞༺♥༻✧