Question
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.
NEET
Physics
Rotational Motion
2025
NEET 2025
NEET Physics Question (2025) — Solution
Options
- A. 100 days
- B. 105 days
- C. 115 days
- D. 108 days
Answer
D. 108 days
Step-by-step solution
Angular Momentum conservation array l|l I _1 _1= I _2 _2 & M = same \\ _2= _1 4 & R _2=2 r _1 \\ T= 2 & I r ^2 \\ & I _2=4 I _1 \\ & ~T _1=27 day array aligned & T _2=4 ~T _1=4 27 \\ & ~T _2=108 days aligned
Related: Physics — Rotational Motion · All PYQ Banks