Astronomy (Edexcel International A Level (IAL) Physics): Exam Questions

Sirius and α-Centauri are two of our closest stars. Sirius has a luminosity about 16 times greater than the luminosity of α-Centauri. Sirius is twice as far away from the Earth as α-Centauri.

The intensity of light from Sirius is I_s and the intensity of light from α-Centauri is I_α .

Which of the following is the value of $\frac{I_s}{I_{\alpha }}$?

The letters W, X, Y and Z represent stars at these positions on the diagram.

Which of the following is part of a possible evolutionary path of a star?

Which of the following statements about stars in positions W, X, Y and Z is correct?

Tau Ceti is one of the closest stars to the Sun. Tau Ceti has a surface temperature of 5300 K and a luminosity of 0.55 L_Sun, where L_Sun is the luminosity of the Sun.

Which of the following is the correct description of Tau Ceti?

Two stars, P and Q, have approximately the same radius. The surface temperature of star P is twice the surface temperature of star Q.

Star P has a luminosity $L_{\mathrm{P}}$ and star Q has a luminosity $L_{\mathrm{Q}}$.

The ratio $\frac{L_{\mathrm{p}}}{L_{\mathrm{Q}}}$ is approximately

A red giant star of surface temperature $T$ and surface area $A$ has a luminosity $L$.

The Sun has a surface temperature of $T_S$, a surface area of $A_S$ and a luminosity of $L_S$.

Which row of the table is correct?