A singly ionized helium ion ( ) contains a nucleus with charge and a single electron
PHYSICS · Multi-part · A Level · Physics · Fields and their consequences · Fields and their consequences
Problem
A singly ionized helium ion (He+) contains a nucleus with charge +2e and a single electron. In a simplified picture, treat the electron as orbiting at a fixed distance of 1.0×10−10m from the center of the nucleus.
1. Calculate the magnitude of the electrostatic force acting on the electron due to the nucleus at this distance.
2. During an electronic transition the electron moves to a higher-energy orbit whose radius is exactly twice as large.
Use the values on the standard reference sheet as needed; treat the nucleus as a point charge located at the origin.
(a) Determine the magnitude of the attractive force on the electron when its orbital radius is 1.0×10−10m.
(b) Determine the magnitude of the attractive force when the electron’s orbital radius becomes 2.0×10−10m.
(c) Calculate the percent decrease in the force from part (a) to part (b).
(d) Briefly discuss how the result obtained in part (c) is consistent with the trend in Coulombic attraction as electron–nucleus separation increases.