Primordial black holes can have masses from a few grams to the mass of a planet. What would be the radius of a primordial black hole with a mass of 10 grams? A) about 5 * 10^-36 m; less than the Planck length! B) about 0.9 *10^-15 m; the charge radius of a proton C) about 3 *10^-15 m; the classical radius of the electron D) about 5 * 10^-11 m; the radius of the lowest electron orbit in hydrogen

Question

Quizplus · Accepted Answer

The radius of a black hole, also known as its Schwarzschild radius, can be calculated using the formula $r_s = \frac{2Gm}{c^2}$, where $G$ is the gravitational constant, $m$ is the mass of the black hole, and $c$ is the speed of light. For a mass of 10 grams, the resulting radius is on the order of $10^{-36}$ meters, which is indeed less than the Planck length, making option A correct.

Primordial Black Holes Can Have Masses from a Few Grams