1lol see the density then :P
What is the largest sizer of earth for which it could have been a blackhole?
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10 Answers
29As we know that escape velocity = √2GM/R
so for earth to be a black hole escape velocity ≥ c (speed of light)
so \frac{1}{2}mc^{2} \leq \frac{GMm}{R}
R \leq \frac{2GM}{c^{2}}
So largest value of R = 8.89*10-3 m
edited the inequality sign...actually the change in potential energy shud be greater than the largest value of KE possible for earth to behave like a black hole so nothing can escape from it's surface..even light..
1thats infact Schwarzschild radius formula ...if i m not ronng :P
black hole radius=2GM/c^{2}
wer m is the mass of earth or for that matter any object
23wat if m = 0 ?? i.e mass less body ?
wat if we consider wave nature of light ?? [6]
1hey i guess largest radius is asked not smallest....abov is the min radius
btw i m not good at des things...
11@ sayonara : It is the max radius . Since gravity follows inverse square law
62govind is right..
I dont know if i shoudl have put this in physics olympiad.. but it was definitely not a jee quesiton inspite of being so easy :P