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JEE Main 2024 (4 Apr, Shift 2) · Applications of Dimensional Analysis

Applications of Dimensional Analysis question from JEE Main 2024 (4 Apr, Shift 2)

Q20JEE Main 2024 · 4 APR · SHIFT 2Easy

Applications of Dimensional Analysis

Applying the principle of homogeneity of dimensions, determine which one is correct, where TT is time period, GG is gravitational constant, MM is mass, rr is radius of orbit.

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Answer: (c)

  1. [G]=[M−1L3T−2][G] = [M^{-1}L^3T^{-2}], so [GM]=[L3T−2][GM] = [L^3T^{-2}].
  2. [r3GM]=[L3][L3T−2]=[T2]\left[\dfrac{r^3}{GM}\right] = \dfrac{[L^3]}{[L^3T^{-2}]} = [T^2], which matches T2T^2.
  3. The other options do not give [T2][T^2].
  4. So the answer is (c) T2=4π2r3GMT^2 = \frac{4\pi^2 r^3}{GM}.
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