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TEST QUESTION 5.1. Most large modern ground-based optical telescopes are reflecting (rather than refraction) telescopes primarily because xA : they provide clearer pictures xB : they are cheaper to build xC : they provide bigger magnification
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TEST QUESTION 5.1 • Most large modern ground-based optical telescopes are reflecting (rather than refraction) telescopes primarily because • xA: they provide clearer pictures • xB: they are cheaper to build • xC: they provide bigger magnification • vD: they can be built with less glass so that they are less likely to be distorted by their own weight
Test question 5.2 • Space telescopes are useful because • xTheyare closer to distant planets and stars • xGravityis reduced in space • vBypassatmospheric absorption of photons in certain wavelength ranges • xSkyis darker in space
Test question 5.3 Jupiter’s distance to the Sun is five times that of the Earth. The Sun’s intensity seen on Jupiter is A:x five times smaller than that on the Earth B:x same as that on the Earth C:x five times larger than that on the Earth D:v twenty five times smaller than that on the Earth.
Test Question 5.4: • A distant galaxy is moving away from the Earth at half the speed of light. The wavelength of its signature atomic hydrogen lines A:x remains unchanged B:v is double C:x is halved D:x is blueshifted
Test question 5.5 Wavelength of Ca emission lines of a nearby star 51 Peg undergo a small amount of periodic sinusoidal changes once every 4 days. This is due to • X the variation of 51 Peg mass • V the reflex motion of the star due to an orbiting planet • X Internal oscillation of 51 Peg, and • X Episodic wind from the surface of 51 Peg
Test question 5.6 • Spectral lines from the atmosphere of distant planets provide valuable information on their A:xatmospheric composition only, B:xatmospheric temperature only, C:xatmospheric rotation only, D:vby all of the above processes
Test question 5.7 • During the transit of a planet COROT 2, (when it moves between its host star and the Earth), astronomers observed some dark lines in its hot star’s spectrum. These lines appear dark because: A:v photons in them are absorbed by the planet’s atmosphere, B:x they are emission lines from the planet, C:x black is the color associated with these wavelengths, D:x paths of the photons are bend by the planet’s gravity
Test question 5.8 • Star Vega is bluer than the Sun. Both stars are on the main sequence. In comparison to that of the Sun, Vega has a • V hotter surface temperature, • X smaller mass • X longer life span • X All the above