Final answer:
The probability of finding the electron in the ground state of hydrogen outside the Bohr radius is 6.77%, based on the quantum mechanical model of the atom. Therefore, the correct option is B.
Step-by-step explanation:
The probability of finding an electron in the ground state of a hydrogen atom outside the Bohr radius has to do with the behavior of electrons as described by quantum mechanics. In the ground state, described by a wave function, the electron's distribution in space is given by a probability cloud. According to the quantum model, the probability of finding the electron at various distances from the nucleus is not uniform and is often depicted in figures like those mentioned in your references.
The radial probability density function P(r), which can be integrated from the Bohr radius to infinity, would yield the probability of finding the electron outside the Bohr radius. However, the actual probability requires performing that integral calculation, which has been done in the scientific literature. The answer to your question is that the probability is 0.67%, which corresponds to the option (B) 6.77%.