Starting From The Ground State Assignment

Assignment 2 1. What is true of light whose frequency is less than |φ 2-φ 1| when starting from the ground state? it can only be absorbed it can be either emitted or absorbed it can only be emitted matter will be transparent to light of this frequency 2. What is true of light whose frequency is equal to |φ 2-φ 1| when starting from the ground state? it can be either emitted or absorbed it can only be emitted it can only be absorbed matter will be transparent to light of this frequency 3. When light of frequency equal to |φ2-φ 1| is absorbed, what happens to the amplitude of the light wave? it is not affected it goes down it goes up 4. A photon has a frequency of 7.6 104 Hz. (a) Convert this frequency into wavelength (nm). 3.9e+12 nm Does this frequency fall in the visible region? Yes No (b) Calculate the energy (in joules) of this photon. 5.0e-29 J (c) Calculate the energy (in joules) of one mole of photons all with this frequency. 3.0e-05 J 5. Observing definite energy amounts associated with specific wavelengths in the emission spectrum of hydrogen would lead one to believe that photons have a smaller rest mass than electrons. electrons have a smaller rest mass than photons. energy states in the hydrogen atom are quantized. the kinetic energy of electrons in the atom may only have certain values, while the potential energy is an arbitrary value. 6. Practice Exercise 7.3 The energy of a photon is 5.61 10-20 J. What is its wavelength (in nanometers)? 3550 nm 7. Select the true statement among the ones presented below. Elements can be identified by their line spectra. Elements in the same family, when combined with oxygen, all have the same line spectra. Elements in the same family and in the same physical state all have the same line spectra. Elements in the same family all have the same line spectra. 8. When copper is bombarded with high-energy electrons, X rays are emitted. Calculate the energy associated with the photons if the wavelength of the X rays is 0.154 nm. 1.29e-15 J 9. The frequency of an electromagnetic wave is the number of complete cycles or oscillations that occur over a distance of one centimeter. distance between successive maxima in any one cycle. number of complete cycles that occur over a one meter distance. number of complete cycles or oscillations that occur in a one second time interval. 10. From the following list of radiation types, select the one that has the longest wavelength. Ultraviolet rays Green visible light Gamma rays Red visible light 11. Which of the following listings starts with the lowest energy of electromagnetic radiation and increases to that which has the greatest energy? Microwave, infrared, visible, ultraviolet Visible, ultraviolet, infrared, gamma rays X-radiation, visible, infrared, microwave Radio, visible, infrared, ultraviolet 12. (a) Calculate the frequency (in Hz) of an electromagnetic wave with a wavelength of 404 m. 7.43e+05 Hz (b) Calculate the frequency (in Hz) of an electromagnetic wave with a wavelength of 684 nm. 4.39e+14 Hz (c) Calculate the wavelength (in nm) of an electromagnetic wave with a frequency of 3.5 1017 Hz. 0.86 nm 13. Which of the following listings starts with the shortest wavelength and increases to the longest wavelength of electromagnetic radiation? microwave, visible, infrared, gamma rays visible, X-rays, infrared, microwave ultraviolet, visible, infrared, microwave radio, infrared, visible, ultraviolet 14. If an infrared radiation has a wavelength of 6.5 10-4 cm, what would this wavelength be when expressed in Angstroms, ? 10-4 3.2 104 6.5 6.5 10-4 4.6 103 15. What is the frequency of visible light having the wavelength of 464.1 nm? 139.1 s -1 1.548 10-15 s -1 6.460 105 s -1 6.460 1014 s -1 16. You are watching a show on the cooking channel where a microwave oven is being used. For this particular oven the radiation has a wavelength of 12.0 cm. Calculate the energy of one photon coming from this oven. 1.66 10-24 J 2.64 10-26 J 1.66 10-32 J 1.66 10-26 J 17. The frequency of the emitted light from a cesium atom is an intensive property. True False 18. The average distance between Mars and Earth is about 1.3 reach Earth? (1 mile = 1.61 km.) 108 miles. How long would it take TV pictures transmitted from the Viking space vehicle on Mars' surface to 7.0e+02 s 19. Practice Exercise 7.5 Calculate the wavelength (in nanometers) of a H atom (mass = 1.674 10-27 kg) moving at 6.00 102 cm/s. 66.0 nm 20. Thermal neutrons are neutrons that move at speeds comparable to those of air molecules at room temperature. These neutrons are most effective in initiating a nuclear chain reaction among 235U isotopes. Calculate the wavelength (in nm) associated with a beam of neutrons moving at 6.20 kg.) 102 m/s. (Mass of a neutron = 1.675 0.638 nm 21. According to de Broglie's equation, the wavelength associated with the motion of a particle increases as the particle mass decreases. True False 22. What is the quantity of energy associated with one photon of light having a wavelength of 464.1 nm? 10-27 4.280 10-12 J 4.280 10-19 J 1.025 10-48 J 2.100 1035 J 23. If the mass of a neutron is 1.00865 a.m.u., calculate (using the de Broglie relation) the wavelength of a neutron which is moving with a speed of 4.505 8.781 10-15 m 2.632 10-3 m 8.781 4.372 10-12 m 10-30 m 24. How many photons at 660 nm must be absorbed to melt 5.0 102 g of ice? (Hint: It takes 334 J to melt 1 g of ice at 0°C.) 5.5e+23 photons On average, how many H2O molecules does one photon convert from ice to water? 3.0e+01 molecules 25. If one mole of photons has a wavelength of 5.461 2.437 10-12 J 1.376 106 J 2.191 2.191 102 mm, calculate its energy in joules. 10-1 J 105 J 26. What is the frequency, expressed in sec-1, for radiation that has an energy of 3.371 1.697 1015 sec-1 5.893 10-7 sec-1 5.087 1.966 1014 sec-1 10-15 sec-1 27. What is the wavelength of radiation that has a frequency of 6.912 4.337 1014 s -1? 102 nm 4.337 10-7 nm 1.447 10-15 nm 2.304 106 nm 2.074 1023 nm 28. Calculate the frequency of visible light having a wavelength of 486 nm. 2.06 1014 /s 2.06 106 /s 1.20 10-15 /s 4.86 10-7 /s 6.17 29. 1014 /s 10-19 joules per photon? 104 m/s. is the energy in joules of a mole of photons associated with visible light of wavelength 486 nm? 6.46 10-16 J 6.46 10-25 J 246 kJ 12.4 kJ 10-4 J 2.46 30. In an electron microscope, electrons are accelerated to great velocities. Calculate the wavelength of an electron traveling with a velocity of 7.0 The mass of an electron is 9.1 103 kilometers per second. 10-28 g. 10-13 m 1.0 1.0 m 1.0 1.0 10-10 m 10-7 m 31. Calculate the wavelength associated with a 20Ne + ion moving at a velocity of 2.0 1.0 10-18 m 2.0 10-13 cm 1.0 105 m/s. The atomic mass of Ne-20 is 19.992 amu. 10-13 m 1.0 10-16 m 9.7 1012 m 32. Calculate the wavelength of a neutron that has a velocity of 200. cm/s. (The mass of a neutron = 1.675 10-27 kg.) 216 nm 1.8 1050 m 198 nm 5.05 mm 1.98 10-9 m 33. The longest wavelength of light that causes electrons to be ejected from the surface of a copper plate is 243 nm. What is the maximum velocity of the electrons ejected when light of wavelength 200. nm shines on a copper plate? 4.67 104 m/s 1.97 104 m/s 1.48 106 m/s 1.34 106 m/s 6.22 105 m/s 34. Electrons can be used to probe the arrangement of atoms on a solid surface if the wavelength of the electrons is comparable with the spacing between the atoms. Which of the following electron velocities would be appropriate for use in this application if the atoms are separated by 0.320 nm? 3.00 108 m/s 2.27 106 m/s 8.06 103 m/s 1.24 103 m/s 4.41 106 m/s 35. A single pulse of a laser yields an average of 5.00 laser pulses need to melt 10.0 g of ice? 1018 photons with = 633 nm. If melting ice to water at 0°C requires 6.01 kJ/mol, what is the fewest number of 3830 38300 212 3340 2120 36. atom. Consider the following energy levels of a hypothetical E4 -1.0 10-19 J E3 -5.0 10-19 J E2 -10 10-19 J E1 -15 10-19 J (a) What is the wavelength of the photon needed to excite an electron from E1 to E4? 142 nm (b) What is the energy (in joules) a photon must have in order to excite an electron from E2 to E3? 5.00e-19 J (c) When an electron drops from the E3 level to the E1 level, the atom is said to undergo emission. Calculate the wavelength of the photon emitted in this process. 199 nm 37. The second line of the Balmer series occurs at a wavelength of 486.1 nm. What is the energy difference between the initial and final levels of the hydrogen atom in this emission process? 4.09 10-22 J 2.44 1018 J 4.09 10-28 J 4.09 10-19 J 10-48 J 1.07 38. Calculate the wavelength of the light emitted by a hydrogen atom during a transition of its electron from the n = 4 to the n = 1 principal energy level. Recall that for hydrogen En = -2.18 10-18 J(1/n2) 82.6 nm 365 nm 6.8 10-18 nm 97.3 nm 0.612 nm 39. Calculate the frequency of the light emitted by a hydrogen atom during a transition of its electron from the n = 4 to the n = 1 principal energy level. Recall that for hydrogen En = -2.18 2.06 1014 /s 1.03 108 /s 3.08 10 -18 J(1/n2) 1015 /s 1.35 10-51 /s 8.22 1014 /s