IB Physics HL E.1.9 Closest approach Question Bank

Practise IB Physics HL E.1.9 by applying closest approach concepts to exam-style physics questions.

Exam points

identify the relevant physical quantity, model or diagram
apply the correct equation and units to the evidence
justify the result using conservation laws, fields or energy relationships

[Maximum number: 2]

In an experiment, alpha particles of initial kinetic energy 5.9 MeV are directed at stationary nuclei of lead $\left({ }_{82}^{207} \mathrm{~Pb}\right)$ . Show that the distance of closest approach is about $4 \times 10^{-14} \mathrm{~m}$ .

2e AND 82e seen

OR

$3.2 \times 10^{-19}$ «C» AND $1.312 \times 10^{-17}$ «C» seen
$d=\frac{8.99 \times 10^{9} \times(2 e)(82 e)}{5.9 \times 10^{6} \times e}=3.998 \times 10^{-14} \approx 4 \times 10^{-14}<\mathrm{m} \gg$

Must see either clear substitutions or answer to at least 4 s.f. for MP2.

All question bank results loaded

E.1.9 (HL)—Closest approach question 1