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Practice5ans - Practice Questions (with answers) Quiz #5...

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Practice Questions (with answers) Quiz #5 material 1. An electron is in a particle-in-a-box potential that has a length of 100 pm, in a state with quantum number, n 1 and energy E 1 . The box is extended to have a length of 200 pm without changing the quantum number n 1 . The energy of the electron in the expanded box is: a. E 1 /4 b. 4E 1 c. E 1 /2 d. E 1 e. not enough information given to answer 2. Calculate the de Broglie wavelength of an electron moving at a speed of 1.00 x 10 3 m s -1 . a. 7.27 x 10 -7 m b. 1.37 x 10 6 m c. 2.73 x 10 -19 m d. 6.03 x 10 -67 m e. none of the above 3. The position of an electron is known to lie within 10 Å (1.0 x 10 -9 m). What is the minimum uncertainty in its velocity? a. 5.27 x 10 -26 m s -1 b. 3.64 x 10 5 m s -1 c. 6.87 x 10 -30 m s -1 d. 5.79 x 10 4 m s -1 e. none of the above
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4. From the following list of observations, choose the one that most clearly supports the conclusion that electrons in atoms have quantized energies. a. the emission spectrum of hydrogen b. the photoelectric effect c. the scattering of alpha particles by metal foil d. diffraction e. cathode rays 5. The classically forbidden region for a one-dimensional finite square well potential described by V = V 0 for x < 0 and x > L, is: a. those values of x for which E < V 0 b. those values of x for which E < 0 c. those values of x for which E > V d. both a. and b. e. both a. and c. 6. An electron in a one-dimensional box requires energy with wavelength 7000 nm to excite it from the n = 2 energy level to the n = 3 energy level. Calculate the length of the box. a. 2.84 x 10 -20 m b. 7.83 x 10 -9 m c. 3.26 x 10 -9 m d. 3.01 x 10 -37 m e. none of these
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7. What is the probability of finding a particle in a one-dimensional box in energy level n = 4 between x = L /4 and x = L /2? ( L is the length of the box) a. 12.5% b. 25% c. 33% d. 37.5% e. 50% 8. Calculate the de Broglie wavelength of a helium atom moving at a speed of 353 m s -1 . a. 3.54 x 10 9 m b. 2.83 x 10 -10 m c. 4.50 x 10 -11 m d. 2.22 x 10 13 m e. none of these 9. For an electron in a 2.00-nm one-dimensional box, calculate the wavelength of electromagnetic radiation to excite the electron from the ground state to the level with n = 3. a. 1650 nm b. 13,200 nm c. 1470 nm d. 12,100 nm e. none of these
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In the hydrogen spectrum, what is the wavelength of light associated with the n = 2 to n = 1 electron transition? a. 1.097 nm b. 364.9 nm c. 0.1097 × 10 –8 cm d. 9.122 × 10 –8 m e. 1.216 × 10 –7 m 11. Calculate the de Broglie wavelength of electrons that have been accelerated to a speed of 1.0 x 10 5 m s -1 . a. 1.15 x 10 -9 m b. 8.63 x 10 8 m c. 1.37 x 10 8 m d. 7.27 x 10 -9 m e. none of these 12. In Bohr's atomic theory, when an electron moves from one energy level to another energy level more distant from the nucleus, a. energy is emitted. b.
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Practice5ans - Practice Questions (with answers) Quiz #5...

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