NTA Abhyas JEE Main2020PhysicsUnits and DimensionsPractice
The dimensional formula of gravitational constant is
Options
- A[ ML 2   T − 2 ]
- B[ ML − 1   T − 1 ]
- C[ M − 1   L 3   T − 2 ]
- DNone of these
Correct answer
C. [ M − 1   L 3   T − 2 ]
Step-by-step solution
From Newton’s law of gravitation, we have: F = G m 1 m 2 r 2 or G = F r 2 m 1 m 2 Substituting the dimensions of all physical quantities: [ G ] = [ MLT − 2 ]   [ L 2 ] [ M ] [ M ] or [ G ] = [ M − 1   L 3   T − 2 ] Its SI unit is m 3     kg - 1   s - 2     or     N   m 2   kg - 2 .