The correct decreasing order of the specific charge ($e/m$ ratio) for an electron ($e$), a proton ($

Question

The correct decreasing order of the specific charge ($e/m$ ratio) for an electron ($e$), a proton ($p$), an alpha particle ($\alpha$), and a Lithium-7 nucleus ($\mathrm{Li}^{3+}$) is

Professor PC Thomas Classes · Answer

(a) : Specific charge is the ratio of charge to mass ($e/m$). For an electron, it's roughly $1/(1/1836) \approx 1836$. For a proton, it's $1/1 = 1$. For an alpha particle (${}^4\mathrm{He}^{2+}$), it's $2/4 = 0.5$. For a $\mathrm{Li}^{3+}$ nucleus (${}^7\mathrm{Li}^{3+}$), it's $3/7 \approx 0.428$. Therefore, the decreasing order is $e > p > \alpha > \mathrm{Li}^{3+}$.