NEET · Physics · STD 11 - 6. system of particles and rotational motion
The Sun rotates around its centre once in 27 days. What will be the period of revolution if the Sun were to expand to twice its present radius without any external influence? Assume the Sun to be a sphere of uniform density.
- A 100 days
- B 105 days
- C 115 days
- D 108 days
Answer & Solution
Correct Answer
(D) 108 days
Step-by-step Solution
Detailed explanation
Angular Momentum conservation
\(T _2=4 T_1=4 \times 27\)
\(T_2=108 \text { days}\)
| \(I _1 \omega_1= I _2 \omega_2\) | \(M=\text { same } \) |
| \(\omega_2=\frac{\omega_1}{4}\) | \( R_2=2 r_1 \) |
| \(T=\frac{2 \pi}{\omega}\) | \( I \propto r^2 \) |
| \( I_2=4 I_1 \) | |
| \( T_1=27 \text { day}\) |
\(T _2=4 T_1=4 \times 27\)
\(T_2=108 \text { days}\)
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