1. Astro/EPS 12 - 2006 Adamkovics Quiz #1: Orbital Motion, Light & Spectra A)1 Astronomical Unit = 1.5 x 10 8 km, Calculate the orbital velocity of the Earth (in km/s) (5 points) B)State four different regions of the electromagnetic spectrum in order of increasing wavelength and give an approximate wavelength (within a factor of 10) for any one of them. (5 points) C)State (at least) five facts that you know about: the information in the spectrum below and/or what is implied about the source of radiation. (1 Point per unique and correct answer up to a maximum of 5 points)

2. Astro/EPS 12 - 2006 Adamkovics Solution 1A: Orbital Motion 1 Astronomical Unit = 1.5 x 10 8 km, Calculate the orbital velocity of the Earth (in km/s) (5 points) Sun Earth 1 AU = 1.5 x 10 8 km circumference period To calculate a velocity, determine the distance traveled over a period of time. In this case the distance traveled is the circumference of Earth’s orbit and the period is the time to complete an orbit -- one year. distance time 2 x  x 1.5x10 8 km 1 year 9.4 x 10 8 km 3.1 x 10 7 sec 9.4 x 10 8 km 1 year x (365 day) x (24 hr) x (3600 sec) (1 year) (1 day) (1 hr) == = = velocity = = 30 km/s In other words, multiply the radius by 2  and convert years to seconds. Think about how you would apply this to other planets.

3. Astro/EPS 12 - 2006 Adamkovics Solution 1B: Electromagnetic Radiation State 4 regions of the electromagnetic spectrum in order of increasing wavelength and give an approximate wavelength (within a factor of 10) for any one of them. (5 points total)

4. Astro/EPS 12 - 2006 Adamkovics Solution #1C: Light & Spectra State (at least) five facts that you know about the information in the spectrum below and/or what is implied about the source of radiation. (1 Point per unique and correct answer up to a maximum of 5) 1.Emission spectrum (not continuum or absorption) 2.Transitions from higher energy levels to lower energy levels 3.Visible region of electromagnetic radiation 4.Atomic (not molecular) emission -- few lines. 5.Hot (or excited) gas at low density (not solid or liquid) 6.Multiple transitions in spectrum, blue lines indicate higher energy than red. 7.Not a sodium spectrum -- because sodium is two yellow lines 8.Having memorized everything in the book, it’s the spectrum of Helium. Some possible answers: