DP Physics (last assessment 2024)

Question 19N.2.HL.TZ0.a(ii)

a(ii).

[Maximum mark: 2]

19N.2.HL.TZ0.a(ii)

In a classical model of the singly-ionized helium atom, a single electron orbits the nucleus in a circular orbit of radius r.

Hence, deduce that the total energy of the electron is given by $E_{TOT} = - \frac{k e^{2}}{r}$ .

[2]

Markscheme

uses (a)(i) to state $E_{k} = \frac{k e^{2}}{r}$ OR states $E_{p} = - \frac{2 k e^{2}}{r}$ ✔

adds « $E_{TOT} = E_{k} + E_{p} = \frac{k e^{2}}{r} - \frac{2 k e^{2}}{r}$ » to get the result ✔

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