Unformatted text preview: Physics 20A: Introduction to Astronomy Homework assignment #1 Due date: October 1 1. Write the following numbers in scientific notation: (a) 237,543.2 (b) 0.0000074 (c) 6 Write the following numbers in ordinary, decimal notation: (d) 4 . 25 × 10 7 (e) 1 . 1 × 10 1 (f) 9 . 85 × 10 5 2. The mean distance between the Earth and the Moon is about 380,000 km. If you point a laser toward the Moon, how many seconds will it take for the light to travel from the Earth to the Moon? 3. (a) Convert a distance of 300 kilometers into units of nanometers. (b) How many minutes are there in 3 gigayears? 4. An electromagnetic wave has a wavelength of 3 cm. What is its frequency in Hertz? 5. In dry air at room temperature, the speed of sound waves is 344 meters per second. The note called “middle C” on a piano keyboard has a frequency of 261.63 Hz. What is the wavelength of a middle C sound wave? 6. Compare the properties of two photons of visible light. One is an violet photon, and one is a red photon.6....
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 Winter '10
 AaronBarth
 Work, Light, Wavelength, Electromagnetic spectrum, surface temperature

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