In classical mechanics, the total energy (E) of a particle moving under an inverse square law force (like the electrostatic force between an electron and a nucleus) determines the nature of its orbit: If E < 0 (Negative Total Energy): The particle is in a bound state. Its orbit is closed and elliptical (with a circular orbit being a special case of an ellipse). The particle is trapped by the central force. If E=0 (Zero Total Energy): The particle is at the boundary between bound and unbound states. Its orbit is open and parabolic. The particle just barely escapes the influence of the central force (it reaches infinity with zero kinetic energy). If E>0 (Positive Total Energy): The particle is in an unbound state. Its orbit is open and hyperbolic. The particle approaches the central force, is deflected, and then moves away to infinity, never to return. It has enough kinetic energy to overcome the attractive potential and escape. Given that the total energy of the electron is positive ( E>0 ), the electron is in an unbound state. This means it will not be trapped in a closed orbit around the nucleus. Instead, it will follow an open trajectory (a hyperbola). Let's evaluate the options: A. electron will revolve in a circular orbit. Circular orbits are closed orbits and correspond to E<0. Incorrect. B. electron will revolve in an elliptical orbit. Elliptical orbits are closed orbits and correspond to E<0. Incorrect. C. electron will not follow a closed orbit. This matches our understanding for E>0, where the orbit is open (hyperbolic). Correct. D. electron will fall into the nucleus. Falling into the nucleus implies a highly negative energy or zero angular momentum, leading to a collision, or continuous energy loss through radiation. A positive energy means the electron has more than enough energy to escape, not fall in. Incorrect. The final answer is C