AQA A Level Physics Paper 3 Section B: Astrophysics June 2019 question paper 7408/3BA

The lenses used in refracting telescopes can cause chromatic aberration.

Complete Figure 1 to show how a lens produces chromatic aberration.

A Cassegrain telescope uses mirrors.

What are the shapes of the primary and secondary mirrors in a Cassegrain

Table 1 contains information about two telescopes, A and B. Each telescope is planned to be the biggest of its type in the world.

Discuss the similarities and differences between optical reflecting telescopes and radio telescopes. Your answer should include references to:

structure

positioning

collecting power.

Go on to discuss which telescope, A or B, will give a more detailed image of an astronomical object that emits both radio waves and visible light.

Table 2 shows some properties of the four brightest stars in the constellation Canis Minor.

Discuss, with reference to the Hipparcos scale, why many star maps show only two stars in the constellation Canis Minor.

State and explain which star in Table 2 has the most prominent Hydrogen Balmer absorption lines.

Deduce which star, Gamma A or HD 66141, has the larger diameter.

Astronomers recently used the radial velocity method to discover an exoplanet orbiting HD 66141.

Describe the main features of the radial velocity method in the detection of planets.

Calculate the distance from the Earth to Procyon. Give an appropriate unit for your answer.

Figure 2 is a Hertzsprung-Russell (HR) diagram.

Label the absolute magnitude axis with a suitable scale.

Label with an S the position of the Sun on the HR diagram.

Draw a line on the HR diagram to show the evolution of a star similar to the Sun from formation to white dwarf.

Label with a P the position on the HR diagram of a star much redder, and with a greater power output, than the Sun.

A star much more massive than the Sun may become a supernova and then a black hole.

Discuss whether supernovae and black holes can be placed on the HR diagram in Figure 2.

Table 3 contains information about two galaxies.

Discuss whether these data are consistent with Hubble’s Law.

Quasars are the most distant measurable objects.

Discuss one problem associated with the determination of the distance from the Earth to a quasar.