As I have already seen that you have answered question nos. 38, 41,42,43, 44 and

Question

As I have already seen that you have answered question nos. 38, 41,42,43, 44 and 45, I am trying to answer question no. 39.

Photoelectric effect is observed when there is a emission of electrons from a metal surface upon exposure to light. In this incident, the light energy is transferred to two part;

1. the kinetic energy of ejected electron and

2. a portion of energy is utilized to eject the electron. This energy is known as "work function" and is solely depends on the nature of metal.

From quantum mechanical calculation, the energy of a light is E=hv. suppose the kinetic energy of ejected electron is Ke and the work function of the metal is Vm.

Therefore, Einstein proposed,

hv=Ke+Vm

Now, the minimum energy required to remove a delocalised electron from the surface of the metal will be

hv=Vm (Kinetic energy is zero)

Now what we have, under the experimental condition green light can not eliminate photo electron therefore for green light hv<Vm . To eject the electron, we need a stronger energy light. blue light have higher frequency(v) than green light. Thus we can expect the photoelectric effect under blue light. If you have red light, it has lower frequency, and elimination of electron is not possible.

Please note, Einstein equation do not have any intensity or distance from source factors. Thus by increasing intensity of minimizing distance from light source does not effect on the photoelectric effect.

Ans. C

Hope this will help. Cheers!!

Explanation / Answer

P. 5 38. What volume (in mL) of 1.000 M HC1O4 is needed to prepare 1.00 L of 0.05000 M HCIO4? A 50.00 B. 100.0 C. 155.0 D. 200.0 E. 500.0 39. In an experiment showing the photoelectric effect, an incident beam of green light produced no ejected electrons from a metal. Which one of the following is most likely to result in electrons ejected from that metal? A. Increase the intensity (brightness) of the green light. B. Move the green light closer to the metal. C. Use blue light instead of green light. D. Use red light instead of green light. E. Use red light and increase its intensity (brightness). The Lewis structure of nitrate ion, NO:, has 3 equivalent resonance structures. What is the average formal charge on each oxygen atom? A.-2 40. B.-1 C. 0 E.-2/3 -41. What is the net ionic equation resulting from a reaction of aqueous solutio n of hydrochloric acid and solid barium hydroxide? A.H+(aq) + OH, (aq) H20(1) B. Ba2"(aq) + 2 Cl-(aq) BaCl2(s) C. 2H+(aq) + Ba(OH)2(s) Ba2+(aq) + 2H20(1) D. 2Cl-(aq) + Ba(OH)2(s) BaCl2(aq) + 2 OH (aq) E. 2HCl(aq) + Ba(OH)2(s) BaCl2(aq) + 2H20(1) which is the equation for which H represents the lattice energy ofNaCl? A. Na(s) + ½ Cl2(g) NaCl (s) B. Na"(g) + Cr(g)-NaCl(s) C. NaCl(g) NaCl(s) -42. D. Na(g) Cl(g) NaCl(s) E. NaCl(s) Na+(g) + Cl-(g) 7.19%S and 42.81960. Its molar mass is 224 g/mol. What is its (SLOS 112 A compound is 5 molecular formula? - 43. 44. To how many significant figures can the answer to (27.053-26.557)/(15.90-15,887)? Note: none of the numbers is exact. A. 1 B. 2 C. 3 D.4 E5 Consider the reaction: 4AI + 3O2 2A1203. If 3.0 mol of Al are mixed with 3.0 mol of Or and the reaction produces 1.0 mol of Al203, what is the percent yield of this reaction? A.75% . 45. B. 90% C. 67% D. 33% E. 50% A rigid container of fixed volume holds 0.10 mol of CH4(g) and 0.20 mol of Ar(g), with a total pressure of 600 Torr. What amount of Ar(g) must be added to the container to increase the total pressure to 900 Torr? A. 0.10 mol B. 0.15 mol C. 0.20 mol D. 0.25 mol E. 0.30 mol 46.

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