20. Here is a simple way to estimate the ground-state energy for a particle in a potential k/r. Suppoee the ground state xnomentum and position satisfies Heisenberg's uncertainty principle pr ~ h, the Kinetic energy in the ground state is Minimize the total energy of the system you find that ground state energy is roughly
(A)
(B)
(C)
(D)
(E) none of the above

16. In a double-slit experiment the slits are 0.5 mmn wide and their centers are separated by 1.5 mm. The interference maxima of what order are missing? (A)m = 2,(B)m= 4, (C)m =6, (D) all above, (E) none of the above.

17. Light strikes a plate in an evacuated chamber. The result is that electrons are etnitted from the plate P and are collected by C. In the process a single'photon gives up all its energy to a singje electron. The maximum poasible kinetic energy of the photoelectrons, , is related to the energy of a photon, hf, by (Φ is work function) (A)(B) (C) (D) hf = 함mยma로 (E) none of the above.

18. Which of the following has the correct dimension of a bulk modulus? (A) Pa,(B)Pa /s, (C)N/m3 (D) kg/m3 (E) none of the above.

19. How does the intensity of radiation changes with the distance r from the source? Let d bo the spatial dimension. (A) proportional to ,(B)proportional to , (C)proportional to, (D) proportional to (E) none of the above.

1. For the reaction 2H2(g) + O2(g)⇌2H2O(g), what is the relationship between K and Kp at temperature T? (A)(B) (C)(D)(E)

2. For a particular system at a particular temperature, there are _______ equilibrium constant(s) and _______ equilibrium position(s). (A) an infinite number of, one (B) one, an infinite number of (C) one, one (D) an infinite number of, an infinite number of (E) none of these

3. Force per impact versus the molar mass of the ideal gas. Which graph represents the plot? (A) (B) (C) (D) (E) none of these

4. Which of the following statements is true concerning ideal gases? (A) the temperature of the gas sample is directly related to the average velocity of the gas particles (B) at STP, 1.0 L of Ar(g) contains about twice the number of atoms as 1.0 L of Ne(8) because the molar mass of Ar is about twice that of Ne (C) a gas exerts pressure as a result of the collisions of the gas molecules with the walls of the container (D) the gas particles in a sample exert attraction on one another (E) all of these statements are false

5. When the equation ； (basic solution) is balanced using the smallest whole- number coefficients, what is the coefficient of ? (A)1(B) 2 (C) 3 (D) 4 (E) 6

6. For the reaction of sodium bromide with chlorine gas to form sodium chloride and bromine, what are the appropriate half-reactions? (ox = oxidation and re = reduction) (A) (B) (C) (D)(E)