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7.Gravitation
medium
If $r$ denotes the distance between the sun and the earth, then the angular momentum of the earth around the sun is proportional to
A
$r^3/r$
B
$r$
C
$\sqrt r$
D
$r^2$
Solution
For an orbit, angular momentum is conserved and this leads to one of Kepler's laws. For a circular orbit angular momentum is
$\mathrm{L}=\mathrm{mvr}=\mathrm{m} \sqrt{\frac{\mathrm{GM}}{\mathrm{r}}} \mathrm{r}$
Hence
$\mathrm{L} \propto \sqrt{\mathrm{r}}$
Standard 11
Physics