Question 23M.3.SL.TZ1.11

L = L_☉ × 52^3.5 = 1.01 × 10⁶L_☉ ✓

Accept back working.

Working should be seen.

L_B = L_A = 10⁶ L_sun ✓

$\frac{L_B}{L_{☉}}=\left(\frac{4\pi {R_B}^2}{4\pi {R_{{}^{\odot }}}^2}\right){\left(\frac{3.0}{6.0}\right)}^4$  OR  1.0 × 10⁶ = ${\left(\frac{R_B}{R_{☉}}\right)}^2\frac{1}{16}$ ✓

$\frac{R_B}{R_{☉}}=\sqrt{1.0\times {10}^6\times 16}=4\times {10}^3$ ✓

Award [3] for BCA

Do not allow ECF from MP2 to MP3.

«star A will evolve into a» red supergiant star✓

will then explode/supernova ✓

creating a neutron star or black hole ✓

« neutron star if core/remnant mass < the Oppenheimer–Volkoff limit/ a black hole if core more massive »

For MP3, award the mark if only one of neutron star OR black hole is mentioned.

$d=\sqrt{\frac{L}{4\pi b}}$ ✓

$d= \sqrt{\frac{2.4\times {10}^{23}}{4\pi \times 4.1\times {10}^{-14}}}$ «$=\frac{6.8\times {10}^{17}}{3.09\times {10}^{16}}$ » ≈ 22 pc

Award [2] for BCA.

For MP1, allow answer in unit m, value 6.8 × 10¹⁷ m.

the distance is well within the limit of about 1000 pc for stellar parallax, so yes it can ✓

Accept 100 pc OR similar distance in other units.

Allow ECF from (d) (also converse argument).