Physics 9702 · AS & A Level · Atoms, nuclei and radiation

Atoms, nuclei and radiation — practice question

A particle with mass $m$ and charge $q$ experiences a uniform electric field of strength $E$. Its acceleration due to the field is $a$.
(a)[2]

Show that, from the given information, $\dfrac{q}{m} = \dfrac{a}{E}$.

(b)[2]

The particle carries charge $4e$, where $e$ is the elementary charge. The electric field strength is $3.5 \times 10^{4}\,\text{V m}^{-1}$, and the particle’s acceleration is $1.5 \times 10^{12}\,\text{m s}^{-2}$. Use the result from part (a) to show that the mass of the particle is $9.0\,\text{u}$.

(c)[1]

The particle is a nucleus. State how many protons and how many neutrons are present in the nucleus.

(d(i))[1]

A second nucleus, which is an isotope of the nucleus in part (c), is placed in the same uniform electric field. State and explain whether the electric field gives the two nuclei the same magnitude of force.

(d(ii))[1]

A second nucleus, which is an isotope of the nucleus in part (c), is placed in the same uniform electric field. State and explain whether the electric field gives the two nuclei the same magnitude of acceleration.

Worked solution & mark scheme

This 7-mark question has a full step-by-step worked solution and mark scheme. One marking point: Hence $E = F/Q$

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