The force acting on the electron in hydrogen atom (Bohr's theory) is related to the principal quantum number n as

Step-by-step solution

According to Bohr's theory of the hydrogen atom, the radius of the n -th orbit is proportional to the square of the principal quantum number, r n^2 . The electrostatic force of attraction acting on the electron is given by Coulomb's law: F = 1 4 ₀ e^2 r^2 Substituting the proportionality of r into the force equation, we get: F 1 (n^2)^2 F n⁻⁴ Alternatively, using the centripetal force expression F = mv^2 r , and knowing that velocity v n⁻¹ and r n^2 , we obtain: F (n⁻¹)^2 n^2 = n⁻⁴ Answer: n⁻⁴