59. A sample of radioactive nuclei of a certain element can decay only by γ -emission and β -emission. If the half-life for γ -emission is 24 minutes and that for β -emission is 36 minutes, the half-life for the sample is
(A) 30 minutes
(B) 24 minutes
(C) 20.8 minutes
(D) 14.4 minutes
(E) 6 minutes

55. The coil shown below has 2 turns, a cross-sectional area of 0.20 m2 , and a field (parallel to the axis of the coil) with a magnitude given by B = (4.0 + 3.0t 2 ) T, where t is in s. What is the potential difference, VA - VC, at t = 3.0 s? (A) -7.2 V (B) +7.2 V (C) -4.8 V (D) +4.8V (E) -12 V

56. A series RLC circuit is connected to an ac source The resistance, capacitive reactance and inductive reactance are 40 Ω, 80 Ω, and 50 Ω respectively. What is the current () in the circuit? (A) 3.0 A (B) 0.040 A (C) 1.7 A (D) 1.4 A (E) 2.4 A

57. The rest mass of an electron isWhat is the kinetic energy of an electron with the speed of 0.80c? (The constant c is the speed of light in vacuum.) (A) (B) (C) (D) (E)

58. In the hydrogen spectrum, the ratio of the wavelengths for Lyman-α radiation (n = 2 to n = 1) to Balmer-α radiation (n = 3 to n = 2) is ______. (A)(B) (C) (D) 3 (E)

60. The radioactive isotope  226Ra decays to 222 Rn with a half-life of 1600 years. The radioactive isotope  238U decays to234 Th  with a half-life of 4.5× 109 years. What is the ratio of the decay rate of 1 g  226Ra to that of 10 g238 U  ? (A) 3.0 × 106 (B) 3.0 × 10-7 (C) 3.0 × 105 (D) 3.0 × 10-6 (E) 3.0 × 107

61. Which of the following solution has shown the correct titration curve? (A) NH3 (B) CO3 2- (C) HCN (D) PO43- (E) NaOH

62. Cisplatin cis-[PtCl2(NH3)2] has been applied as an anti-tumor drug. What is its main interaction in vivo? (A) Binding with DNA. (B) Binding with lipid. (C) Binding with protein. (D) Binding with sugar. (E) Blocking ion absorption.

63. A chemist needs to prepare a buffered solution using one of the following acids (and its sodium salt): HA (Ka = 1.4 × 10-3 ), HB (Ka = 9.8 × 10-6 ), HC (Ka = 8.4 × 10-5 ), HD (Ka = 3.5 × 10-7 ), HE (Ka = 1.9 × 10-8 ). To prepare a solution buffered at pH = 5.10, which system will work best (a buffer with the best capacity)? (A) HA and its sodium salt (B) HB and its sodium salt (C) HC and its sodium salt (D) HD and its sodium salt (E) HE and its sodium salt

64. Of the following eleven compounds, how many of them have aromatic character? (A) 3 (B) 4 (C) 5 (D) 6 (E) 7

65. Which of the following species has the lowest dissociation energy? (A) O2 (B) O2 – (C) O2 2– (D) O2+ (E) O2 2+