ASTR 1P01/02: Introduction to Astronomy I/II
Practice Questions

Please solve the following questions. This is not an assignment, it will not be graded, and you do not need to submit your solutions to anyone. The questions are simply intended to help you practice for the exam.

These questions will not appear in the exam itself. Students who don't genuinely attempt to solve the questions on their own, and only memorize the solutions, will have a very hard time in the actual exam!

These questions are not multiple-choice, to encourage you to think of the answers on your own, but the questions in the actual exam will be multiple-choice.

If you need any clarifications for these questions, you can ask for them on the course Teams channel.

Question 1

What is the difference between luminosity and apparent magnitude?

Question 2

Star A has apparent magnitude 5.5. Star B has apparent magnitude 8.5. Which star is brighter?

Question 3

Star A has apparent magnitude -2.6. Star B has apparent magnitude -6.1. Which star is brighter?

Question 4

Star A has apparent magnitude -7.2. Star B has apparent magnitude 1.5. Which star is brighter?

Question 5

A star is located 20 ly away from Earth. How bright will the same star look to aliens living on a planet 100 ly away from the star?

Question 6

Vega has an apparent magnitude of +0.03. Under what conditions is it visible?

Question 7

What is the difference between apparent and absolute magnitude?

Question 8

Is light a continuous wave, or is it made of discrete particles?

Question 9

Wave A has frequency 100 Hz. Wave B has frequency 50 Hz. Which wave has a longer wavelength?

Question 10

Photon A has energy 30 eV. Photon B has energy 20 eV. Which photon has a higher frequency?

Question 11

I am wearing a green shirt. What range of wavelengths of light is being reflected from my shirt?

Question 12

Which has a higher frequency: microwaves or X-rays?

Question 13

Body A has temperature 1000 K. Body B has temperature 2000 K. Which body's blackbody radiation has a longer peak wavelength?

Question 14

Explain why the sky is blue and why the Sun appears red/orange/yellow.

Question 15

What is the speed of light in meters per second? The average human walking speed is around 1.5 meters per second; how long will it take a human to walk the distance that light travels in one second?

Question 16

If I double the frequency of an electromagnetic wave, what happens to its wavelength?

Question 17

How would the intensity of a distant star change if the distance to the star was tripled?

Question 18

Why did humans and other animals on Earth evolve to see the 400-700 nm range of the electromagnetic spectrum?

Question 19

How does a photon's wavelength relate to its energy?

Question 20

I heat two containers of gas. One is helium and the other is neon. Do they emit the same wavelengths of electromagnetic radiation?

Question 21

What's the difference between an absorption spectrum and an emission spectrum?

Question 22

What happens if I put an absorption spectrum on top of an emission spectrum?

Question 23

What is an energy level?

Question 24

An electron moves from an orbit with energy level 1 eV to an orbit with energy level 3 eV. Will it emit or absorb a photon? What would be the energy of this photon?

Question 25

What produces a photon with a longer wavelength: an electron moving from energy level 5 eV to 4 eV or from 5 eV to 3 eV?

Question 26

What is the difference between the ground state and an excited state?

Question 27

What is ionization? When does it happen?

Question 28

A car is driving from Alice to Bob. The car sounds its horn, which produces sound waves that propagate in all directions. According to the Doppler effect, what is the difference between what Alice hears and what Bob hears, in terms of wavelength, frequency, and pitch?

Question 29

A white spaceship is moving away from Earth at a very high speed. What will happen to its color as seen by people observing it from Earth?

Question 30

How can we detect the elements inside a star even though their spectral lines have been shifted due to the Doppler effect?

Question 31

Rank the following stars from hottest to coolest: F2, K9, F8, A4, A3, K7.

Question 32

Summarize how astronomers use spectrography to measure the size, composition, velocity, and rotation of stars.

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