MCQ
A metallic solid sphere is rotating about its diameter as axis of rotation. If the temperature is increased by 200°C, the percentage increase in its moment of inertia is : (coefficient of linear expansion of the metal = 10-5/°C)
  • A
    $0.1$
  • B
    $0.2$
  • C
    $0.3$
  • $0.4$

Answer

Correct option: D.
$0.4$
$ 0.4$
Solution :
$I  =\frac{2}{5} MR ^2$
$\frac{\Delta I }{ I }  =2 \frac{\Delta R }{ R }=\frac{2 R \alpha \Delta t}{ R }=2 \alpha \Delta t $
$\frac{\Delta I }{ I }  =2 \times 10^{-5} \times 200=4 \times 10^{-3}$
{ Percentage increase }$=4 \times 10^{-3} \times 100=0.4$

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