Q. If the constant of gravitation $(G)$, Plank’s constant $(h)$ and the velocity of light $(c)$ be chosen as fundamental units. The dimension of the radius of gyration is

A) $h^{1/2}c^{- 3/2}G^{1/2}$
B) $h^{1/2}c^{3/2}G^{1/2}$
C) $h^{1/2}c^{- 3/2}G^{- 1/2}$
D) $h^{- 1/2}c^{- 3/2}G^{1/2}$
Explanation

Let radius of gyration $\lbrack k\rbrack \propto \lbrack h\rbrack^{x}\lbrack c\rbrack^{y}\lbrack G\rbrack^{z}$ By substituting the dimension of $\lbrack k\rbrack = \lbrack L\rbrack$ $\lbrack h\rbrack = \left\lbrack ML^{2}T^{- 1} \right\rbrack$ $\lbrack c\rbrack = \lbrack LT^{- 1}\rbrack$ $\lbrack G\rbrack = \lbrack M^{- 1}L^{3}T^{- 2}\rbrack$ And by comparing the power of both sides We can get $x = 1/2,\ y = - 3/2,\ z = 1/2$ Therefore dimension of radius of gyration is $\lbrack h\rbrack^{1/2}\lbrack c\rbrack^{- 3/2}\lbrack G\rbrack^{1/2}$

Dr. Abubacker
Reviewed by Dr. Abubacker

Physics Educator & NEET/JEE Specialist

Ph.D. in Physics with 19+ years of teaching experience.