Question 30 (Revised): If the universal gravitational constant G, Planck's constant h, and the speed of light c are taken as fundamental units, what is the dimension of Length in this new system?

4 views 0 helpful Updated Jul 27, 2026
Appears in NEET UG
Solution ✔ Verified
  • AG¹/2 h¹/2 c^-3/2
  • BG¹/2 h¹/2 c^-5/2
  • CG¹/2 h^-1/2 c¹/2
  • DG^-1/2 h¹/2 c³/2
Explanation

We need to find x, y, z such that [L] = [G]^x [h]^y [c]^z. Substituting the dimensions: [G] = [M^-1 L³ T^-2], [h] = [M L² T^-1], [c] = [L T^-1]. Equating powers of M, L, T: M: 0 = -x + y L: 1 = 3x + 2y + z T: 0 = -2x - y - z Solving these equations gives x=1/2, y=1/2, z=-3/2. So, [L] = G^(1/2) h^(1/2) c^(-3/2).

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