Assignment:
1. Which one of the following statements about atoms is false?
(a) Their electrons have discrete energy levels.
(b) Each element produces a unique pattern of spectral lines, like a fingerprint.
(c) Photon emission can occur randomly, in any direction,
(d) An electron in an atom may absorb either part or all of the energy of a photon.
(e) During absorption of a photon, an electron in an atom jumps from a lower energy level to a higher energy level.
2. A local radio station broadcasts at 100.3 MHz (a megahertz =106 cycles per second. What is the approximate wavelength of its signals? (Light travels about 30 cm in 1ns.)
(a) 3,000 angstroms.
(b) 30 meters.
(c) 1.86 miles.
(d) 30 centimeters.
(e) 3 meters.
3. A star has two times the surface temperature & one half the diameter as our Sun. How much more or less luminous is it than the Sun?
(a) 16 times more
(b) 4 times more
(c) 2 times more
(d) it's the same
(e) 2 times less
4. Which type of "telescope" cannot be used for ground-based observations?
(a) a radio telescope
(b) an infrared telescope
(c) an X-ray
(d) telescope
(e) none of the above
5. Telescope A has a mirror 10 m in diameter, while telescope B has a minor 2 m in diameter. The focal length of telescope A is twice the focal length of telescope B. When both telescopes are being used from the same location and in the same manner, the faintest stars A can detect are times fainter than the faintest stars B can detect.
(a) 5 (the ratio of the diameters)
(b) 10 (the ratio of the diameters times the ratio of the focal lengths)
(c) 12.5 (the ratio of the areas divided by the ratio of the focal lengths)
(d) 25 (the ratio of the areas)
(e) 50 (the ratio of the areas times the square of the ratio of the focal lengths)
6. Which one of the following statements about telescopes is false?
(a) The light-gathering power is proportional to the square of the diameter.
(b) Atmospheric turbulence can limit the angular resolution (clarity).
(c) Reflecting telescopes can suffer from chromatic aberration.
(d) The angular resolution (clarity) of a telescope is better at shorter wavelengths.
(e) All of the above statements are true.