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The energy of an electron in hydrogen at...

The energy of an electron in hydrogen atom is -3.4 eV, then its angular momentum is ......

A

`2.1xx10^(-34)Js`

B

`2.1xx10^(-20)Js`

C

`4xx10^(-20)Js`

D

`4xx10^(-34)Js`

Text Solution

Verified by Experts

The correct Answer is:
A
`E_(n)=-(13.6)/(n^(2))`
`:.-3.4=-(13.6)/(n^(2))`
`:.n^(2)=(13.6)/(3.4)=4`
`:.n=2`
`:.` Angular momentum in `n^(th)` orbit,
`L_(n)=(nh)/(2pi),n=2`
`L_(2)=(2h)/(2pi)=(h)/(pi)=(6.625xx10^(-34))/(3.14)=2.109xx10^(-34)`
`:.L_(2)~~2.5xx10^(-34)Js`
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