Stars and the Universe

What is the approximate time taken by light from the Sun to travel to the Earth?

Options

A   $0.50\ \text{s}$
B   $5.0\ \text{s}$
C   $50\ \text{s}$
D   $500\ \text{s}$

A star is a distance of 4.2 light-years from the Earth.

What is 4.2 light-years in metres?

Options

A   $1.1 \times 10^{13}\ \text{m}$
B   $6.6 \times 10^{14}\ \text{m}$
C   $9.5 \times 10^{15}\ \text{m}$
D   $4.0 \times 10^{16}\ \text{m}$

What is a protostar?

Options

A   a cloud of gas that is collapsing and decreasing in temperature
B   a cloud of gas that is collapsing and increasing in temperature
C   a star that is expanding and decreasing in temperature
D   a star that is expanding and increasing in temperature

A teacher asks two students to describe redshift.

Student 1 says: It is a decrease in the observed wavelength of electromagnetic radiation from stars.

Student 2 says: It occurs because stars and galaxies move away from the Earth.

Which students are correct?

Options

A   both student 1 and student 2
B   student 1 only
C   student 2 only
D   neither student 1 nor student 2

What is the nuclear reaction that powers the Sun?

Options

A   the fission of hydrogen into helium
B   the fission of helium into hydrogen
C   the fusion of hydrogen into helium
D   the fusion of helium into hydrogen

A student spills ink on the page in a textbook that defines redshift. The ink covers the three important words 1, 2 and 3.

Redshift is ______(1) in the observed ______(2) of electromagnetic radiation emitted from ______(3) stars and galaxies.

What are words 1, 2 and 3?

Options

What is never formed by the explosion of a red supergiant?

Options

A   a black hole
B   a neutron star
C   a white dwarf
D   new heavier elements

What is the nuclear reaction that takes place in stable stars?

Options

A   fission of helium to produce hydrogen
B   fission of hydrogen to produce helium
C   fusion of helium into hydrogen
D   fusion of hydrogen into helium

Four of the stages in the life cycle of a star, until it becomes a red giant, are shown.

1. Inward force of gravitational attraction is balanced by an outward force from its centre.
2. Internal gravitational collapse produces an increase in temperature.
3. It expands.
4. Most of the hydrogen has been converted to helium.

In which order do these stages occur, starting with the earliest?

Options

A   $\text{W} \rightarrow \text{X} \rightarrow \text{Y} \rightarrow \text{Z}$
B   $\text{W} \rightarrow \text{X} \rightarrow \text{Z} \rightarrow \text{Y}$
C   $\text{X} \rightarrow \text{W} \rightarrow \text{Y} \rightarrow \text{Z}$
D   $\text{X} \rightarrow \text{W} \rightarrow \text{Z} \rightarrow \text{Y}$

What is the first stage in the life cycle of stars?

Options

A   a black hole
B   a cloud of gas and dust
C   a red supergiant
D   a supernova