[الأمير المدريدي]

المشاركة الأصلية كتبت بواسطة الأمير المدريدي لو سمجتوا ايش طريقة حل هذه الاسئلة في شابتر 7 20 . 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? A. 1.48 × 106 m/s b. 6.22 × 105 m/s c. 4.67 × 104 m/s d. 1.97 × 104 m/s e. 1.34 × 106 m/s 21. When photons with a wavelength of 310. Nm strike a magnesium plate, the maximum velocity of the ejected electrons is 3.45 × 105 m/s. Calculate the binding energy of electrons to the magnesium surface. A. 386 kj/mol b. 419 kj/mol c. 32.7 kj/mol d. 321 kj/mol e. 353 kj/mol 65. Which of these atoms is diamagnetic both in its ground state and in all of its excited states? A. Mg b. Ne c. Cu d. Zn e. None of these 66. The electron in a hydrogen atom falls from an excited energy level to the ground state in two steps, causing the emission of photons with wavelengths of 2624 and 97.2 nm. What is the quantum number of the initial excited energy level from which the electron falls? A. 2 b. 3 c. 4 d. 6 e. 8 67. The electron in a hydrogen atom falls from an excited energy level to the ground state in two steps, causing the emission of photons with wavelengths of 1870 and 102.5 nm. What is the quantum number of the initial excited energy level from which the electron falls? A. 2 b. 3 c. 4 d. 6 e. 8 68. When the electron in a hydrogen atom falls from the n = 3 excited energy level to the ground state energy level, a photon with wavelength λ is emitted. An electron having this same wavelength would have a velocity of a. 7.10 × 103 m/s. B. 2.93 × 106 m/s. C. 2.93 × 103 m/s. D. 7.10 m/s. E. 3.00 × 108 m/s. 69. When the electron in a hydrogen atom falls from its first excited energy level to the ground state energy level, a photon with wavelength λ is emitted. A proton having this same wavelength would have a velocity of a. 3.87 m/s. B. 5990 m/s. C. 1.21 × 10-7 m/s. D. 3.26 m/s. E. 5.99 m/s. 70. Breaking the oxygen-oxygen bond in hydrogen peroxide requires 210 kj/mol. What is the longest wavelength of light that can cause this bond to be broken? A. 5.7 × 10-4 m b. 9.5 × 10-31 m c. 2.8 × 10-7 m d. 9.5 × 10-28 m e. 5.7 × 10-7 m 71. A photovoltaic cell converts light into electrical energy. Suppose a certain photovoltaic cell is only 63.5% efficient, in other words, that 63.5% of the light energy is ultimately recovered. If the energy output of this cell is used to heat water, how many 520 nm photons must be absorbed by the photovoltaic cell in order to heat 10.0 g of water from 20.0°c to 30.0°? [given: The specific heat of water is 4.184 j/g·°c.] a. 4.12 × 1020 b. 1.72 × 1021 c. 2.62 × 1020 d. 6.95 × 1020 e. 1.10 × 1021

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