Gravitation Question 11
Question 11 - 30 January - Shift 1
If the gravitational field in the space is given as $(-\frac{K}{r^{2}})$. Taking the reference point to be at $r=2 cm$ with gravitational potential $V=10 J / kg$. Find the gravitational potential at $r=3 cm$ in SI unit (Given, that $K=6 J cm / kg$ )
(1) 9
(2) 11
(3) 12
(4) 10
Show Answer
Answer: (2)
Solution:
Formula: Universal Law of Gravitation, Gravitational Potential
$-\frac{dV}{dr}=-\frac{k}{r^{2}} \Rightarrow \int _10^{V} dV=\int_2^{3} \frac{k}{r^{2}} dr$
$V-10=k[\frac{1}{2}-\frac{1}{3}]$
$V-10=\frac{k}{6} \Rightarrow V=11$ volts
