Astro 150 S 2024 Exam 1 Review Quiz

If the star Tau Ceti is 12 lightyears away from earth, when did the light we're now seeing from that star leave that star?

• 2019

• 2023

• 2012

• 12

Answer explanation

One light year is how far light travels in a year, so if Tau Ceti is 12 light years away, it took the light from Tau Ceti 12 years to get here. So, the light that we're seeing now from that star left in 2012

What is the Copernican Revolution?

• The transition from commonly using a geocentric solar system model to a heliocentric one

• The transition from commonly using a heliocentric solar system model to a geocentric one

• The technically correct name of the year after adopting the Copernican model

• The transition from using intuition to using empirical evidence to understand the Universe

Answer explanation

While the adoption of the heliocentric solar system model may have been part of the Copernican revolution, the overall revolution was the change in how we learn about the Universe.

Which of these should we NOT see in a geocentric model that we should see in a heliocentric one?

• Retrograde planetary motion

• Trigonometric parallax of stars

• The planet Neptune

• Solar eclipses

Answer explanation

Because the Earth is moving in the heliocentric model, we should see trigonometric parallax of distant stars. The stationary nature of the Earth in the geocentric model does not call for parallax at all. It wasn't until fairly recently that these parallaxes could be seen, which is one reason why the heliocentric model took so long to gain traction.

According to Kepler's third law...

• Some seasons are shorter than others

• Planets farther from the Sun will have longer periods

• Planets orbit the Sun in elliptical orbits

• For every action, there is an equal and opposite reaction

Which force is responsible for radio waves?

• Gravitational force

• Weak nuclear force

• Electromagnetic force

• Strong nuclear force

• The Force

Answer explanation

Radio waves are a type of light wave, and light waves are electromagnetic waves.

What CAN'T light tell us?

• An object's motion through space

• An object's temperature

• An object's composition

• Light can tell us all of these

Which of these is NOT intrinsic to a star?

• Luminosity

• Temperature

• Brightness

• Mass

Which of these has the SHORTEST peak blackbody radiation wavelength?

• A red-hot oven coil

• You

• A lump of charcoal

• The Sun

In which situation is Star 1 more luminous?

• Star 1 has half the temperature of Star 2, but four times the radius

• Star 1 has double the radius of Star 2, but half the temperature

• Star 1 has the same temperature and radius as Star 2, but it is twice as far away

• Star 1 has double the temperature of Star 2, but half the radius

7. What happens to an electron in an atom that produces an emission line?

• It goes to a lower energy orbit

• It goes to a higher energy orbit

• Nothing

• It becomes unbounded to the atom

Answer explanation

The electron goes to a lower orbit, producing an emission line. An absorption line is produced if the electron goes to a higher orbit.