30. Which of the options below shows an INCORRECT chemical formula for the named compound?
(A) iron(II) oxide FeO
(B) potassium sulfate K₂SO₄
(C) sodium sulfide NaS
(D) zinc nitrate Zn(NO₃)₂
(E) calcium carbonate CaCO₃

26. Polystyrene is an addition polymer of styrene. What would be the effect, if some divinylbenzene were added to styrene and then polymerized? (A) The polymer would be more flexible. Divinylbenzene acts as a plasticizer. (B) The polymer would be less flammable than pure polystyrene. (C) There would be an effect, but it cannot be predicted. (D) There would be no effect on the properties of the polymer. (E) Divinylbenzene would act as a cross-linking agent, making the polymer stronger.

27. Which of the following quantum model is most adequate as an approximation to describe an t-electron moving in ẞ-carotene? (A) a particle in a one-dimensional box (B) harmonic oscillator (C) a freely moving particle (D) rotation in two dimensions (E) a rigid rotor

28. Consider the reaction 2NO2(g) → 2NO(g) + O2(g). The concentration of NO2 was measured to be 0.0038 mol/L after 200 s and 0.0033 mol/L after 250 s. Calculate the reaction rate for NO2. (A) (B)(C) (D)(E)

29. A liquid above the packed solid following a centrifugation is called the _____(A) solvonatant (B) analyte (C) serum (D) decanted (E) supernatant

31. During the heart's beating process, the activity of cardiomyocytes generates a magnetic field in space. In 1963, Baule and others first recorded the magnetic field generated by the electrical currents in the human heart, leading to the development of magnetocardiography (MCG). Using the Biot-Savart law to estimate the magnetic field. Suppose that I = A is the total current generated by myocardial activity and r = 0.1 m is the distance to the measurement point, what is the order of magnitude of the magnetic field generated by the heart in T? The permeability of free space is µ0=1.26× (T·m/A). (A)T (B) T (C) T (D)T (E) T

32. A particle moving in circular motion on a plane with a radius r has an angular momentum L and mass m. Which of the following expressions represents the centripetal force F of this circular motion? (A) F = mr²L (B) (C) F = rmL (D) (E)

33. Two concentric conducting spheres have an inner sphere of radius a and an outer sphere of radius b. One terminal of a battery is connected to the outer sphere, while the other terminal is grounded (see Figure). What is the capacitance of this system? (A)(B) C = 4πε0(a+b) (C)(D) C = 4πε0β (E) Ο = 4πε0α

34. A beam of light traveling from point A to point B (see Figure) undergoes refraction as the figure shows. If the refractive indices of the top and bottom media are n₁ and n2, respectivly, what is the ratio ? (A) 2/3 (B) 3/2 (C) √8/3 (D) 3/√8 (E) √2/1

35. Consider the circuit in the Figure and assume the battery has no internal resistance. Just after the switch is closed, what is the current in the battery? (A) 0 (B) ε/2R (C) 28/R (D) ε/R (Ε) ε/3R

36. For any given scattering angle 8, this equation gives the same value for the Compton shift for any wavelength. Keeping that in mind, for which of the following types of radiation is the fractional shift in wavelength at a given scattering angle the largest? (A) radio waves (B) microwaves (C) visible light (D) x-rays (E) infrared