KEAM 2019 Physics and Chemistry Paper

Angular momentum of an electron in an orbital of an atom (L)=mvr
To find out the units,
L=mv×r=kg×ms−1×m
L=kgm2s−1.....(i)
We know that, 1 Joule =kgm2s−2
Multiplying and dividing Eq. (i) by s−1
L=kgm2s−1×‌s−1∕s−1
=kgm2‌

s−2

s−1

L=J−s
Hence, the unit for angular momentum of an electron in an orbital is J−s.