Question

What upper limit for the radius of the gold nucleus follows from the calculated distance of closest approach?

Options

• Exactly \[3.84\times10^{-16}\,\mathrm{m}\]

• Greater than \[3.0\times10^{-14}\,\mathrm{m}\]

• Exactly \[3.0\times10^{-14}\,\mathrm{m}\]

• Less than \[3.0\times10^{-14}\,\mathrm{m}\]

Answer 1

The alpha particle reverses direction at a centre-to-centre distance of \[3.0\times10^{-14}\,\mathrm{m}\]. The gold nucleus’s radius must be less than this distance; the distance is not its exact radius.