CHAPTER ONE QUIZ!

Question 1. What is the electron behaviour in the emission and absorption spectrum?

In both types of spectum the electrons change from a ground state to an excited by taking energy.
ln both types of spectrum electrons transit from a higher energy state to a lower one.
In the absorption spectrum electrons change from a ground state to an excited by taking energy. In the emission spectrum, electrons transit from a higher energy state to a lower one.
In the emission spectrum electrons change from a ground state to an excited by taking energy. In the absorption spectrum, electrons transit from a higher energy state to a lower one.

Question 2. How can astronomers take advantage of dual perspective?

They can find extrasolar planets and brown dwarfs from dual perspective measurements.
They can measure the distance to a star from the shift of its position when compared to a pattern of more distant stars.
They can calculate the radiation energy per unit time from the apparent change in direction of the remote object due to a change in vantage point of the observer.
They can obtain the distance of a star from Earth through the wavelength at which it emits the most light.

Question 3. How many kilometers is a light year?

9.5 billion km.
9 500 000 000 km.
9 500 000 000 000 km.
950 trillion km.

Question 4. Which of the following sentences is referring to radial-velocity method?

Doppler spectroscopy is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star.
A planet moves in its ellipse, so the line between it and the star placed at a focus cover equal areas in equal times.
Wien's displacement law links the temperature of a blackbody and the wavelength at which it emits the most light.
An ancient Greek astronomer named Hipparchus (190 B.C.E.- 120 B.C.E.) invented the first Magnitude scale to measure the velocity of stars. He gave the fastest stars he could see a value of 1 and the slowests a value of 6.

Question 5. An astronomer wants to use a telescope from Earth. How can she avoid atmospheric interferences in order to produce images as sharp as if the telescope was in space?

Creating an artificial star in the Earth's athmosfere so that, as this star is nearer, the picture would be as if the telescope was in space.
Creating an artificial guide star in the Earth's athmosfere in order to obtain its energy spectrum which would permit to adjust the optic lenses.
Launching a laser beam from a big telescope. This laser would permit to neglect Earth's rotation velocity and the pictures would not be blurred.
Know the atmospheric interferences would permit to avoid them. For achieve that, the telescope has not to take overexposed pictures, so she has to go somewhere with no light pollution.

Question 6. What a variable star is?

A star which is usually eclipsed by Big Jupiter so, from Earth's vantage point, its brightness vary.
A star seen to vary in brightness.
A star system consisting of two stars orbiting a common center of mass.
A very bright star.

Question 7. An astronomer wants to know the radius of Sirius. If he had already determined Sirius temperature and luminoxity, what law formula should he use?

Stefan-Boltzmann's law formula.
Wien's law formula.
Kepler's third law of planetary motion formula.
Kepler's second law of planetary motion formula.

Question 8. The universe is expanding and, among many other reasons, we know it for the contribution of the american Edwin Hubble (1889-1953) in the field of astronomy. What had he recorded?

Hubble recorded the blueshift of the spectrum of extragalactic nebulae, which means that the galaxies are moving towards the Earth.
Hubble recorded the blueshift of the spectrum of extragalactic nebulae, which means that the galaxies are moving away Earth.
Hubble recorded the redshift of the spectrum of extragalactic nebulae, which means that the galaxies are moving towards the Earth.
Hubble recorded the redshift of the spectrum of extragalactic nebulae, which means that the galaxies are moving away Earth.

Question 9. What the transit method is?

It is a method based on the measurement of the intensity of light to detect the presence of one or more exoplanets in orbit around a star.
It is an indirect method for finding extrasolar planets and brown dwarfs from radial-velocity measurements via observation of shifts in the spectrum of the planet's parent star.
It is a method which indirectly links luminoxity from a black body and the temperature and surface of a star.
It is a method based on the electron transition from a higher energy state to a lower and vice versa.

Question 10. What is a black body?

It is a hypothetical perfect absorber and radiator of energy, with no reflecting power.
It is surface that absorbs all radiant energy falling on it. In other words, incident visible light will be absorbed rather than reflected, and therefore the surface will appear white.
It is an ideal body or surface that completely absorbs some radiant energy falling upon it with no reflection.
In an ideal sense, it is an object that does not absorb all electromagnetic radiation that falls on it, the radiation pass through it or is reflected by it.