Largest blackhole of mass of earth...

As 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..

lol see the density then :P

thats 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

wat if m = 0 ?? i.e mass less body ?

wat if we consider wave nature of light ?? [6]

hey i guess largest radius is asked not smallest....abov is the min radius

btw i m not good at des things...

@ sayonara : It is the max radius . Since gravity follows inverse square law

wat do u mean by R≥k
that means k is the min value of R

brother i think we have to include the theory of relativity.

ya something may be lik that [3]