Verified Solution • 2025–26 Session moderate

QNEET-2023-Ph-254: NEET 2023 Physics - Class 11 NEET-2023-Ph-254 Solution: The ratio of radius of gyration of a solid sphere of mass M and …

The ratio of radius of gyration of a solid sphere of mass M and radius R about its own axis to the radius of gyration of the thin hollow sphere of same mass and radius about its axis is :- 5:3 2:5 5:3\sqrt{5}:\sqrt{3} 3:5\sqrt{3}:\sqrt{5}

Multiple Choice Options

  • A 5:35: 3 5 : 3
  • B 2:52: 5 2 : 5
  • C 5:3\sqrt{5}: \sqrt{3} 5 _ : 3 _
  • D 3:5\sqrt{3}: \sqrt{5} 3 _ : 5 _

Step-by-Step Verified Solution

To solve this problem, we need to find the ratio of the radius of gyration for a solid sphere (K_) to the radius of gyration for a thin hollow sphere (K_) of the same mass M and radius R. The moment of inertia (I) of a solid sphere about its own axis is given by : I s o l i d = 2 5 M R 2 The radius of gyration (K) is related to the moment of inertia (I) and mass (M) by the formula : I = M K 2 So for the solid sphere, we can find K_ using : K 1 2 = I s o l i d M = 2 5 R 2 K 1 = R 2 5 Now, for a thin hollow sphere, the moment of inertia about its axis is given by : I h o l l o w = 2 3 M R 2 We can find K_ using : K 2 2 = I h o l l o w M = 2 3 R 2 K 2 = R 2 3 Now, we need to find the ratio K_ : K_ : K 1 K 2 = R 2 5 R 2 3 The R terms cancel out, and we are left with : K 1 K 2 = 2 5 2 3 Simplify by taking the square root of the fraction : K 1 K 2 = 2 3 5 2 Now, the square root of 2 terms cancel out, giving us : K 1 K 2 = 3 5

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