(Solved): 20. A seientibf reports that his measurement of the temperature of the surtace of a newly diseovere ...

20. A seientibf reports that his measurement of the temperature of the surtace of a newly diseovered comet is $-20\mathrm{K}$. What conclusion can vou draw from this report.,? A) the solentiat must have measured the dark side of the comet, away trom the Sun: B) the comet must be a very long wary from the Sum; C) the sclentiat must be smoking something tunny, sinee nothing is colder than absolute zero $(0\mathrm{K})$ : D) the comet is relatively warm, since $-20\mathrm{K}$ is same temperature as $-10^{\circ }\mathrm{F}$. 21. The position of an element on the periodic table is directly related to A) the number of protons in the nucleus of an atom; B) the total number of protons and neutrons in the nucleus of an atom; C) the number of electrons in the energy levels, and hence its electric charge; D) the mass of one atom of that element, measured in AMU. 22. Which of the following electromagnetic waves has the longest wavelength..? Also, which type of wave has the most energy...? A) X-rays, visible light: B) Gamma rays , radio waves; C) HF radio waves, gamma rays; D) visible light, gamma rays. 23. Spectral lines (emission lines) are created by an ionized element when: A) the element's nucleus undergoes fusion with a hydrogen atom; B) an electron falls back into a lower energy shell, releasing the excess energy as a photon of light; C) an electron absorbs an energetic photon and jumps to a higher energy level; D) an atom undergoes ionization due to an electric charge.