177- In a photoelectric experiment, the maximum velocity of photoelectrons emitted from the metal surface is $5\times10^5\ \frac{\text{m}}{\text{s}}$. If the work function of the metal is $3.66\ \text{eV}$, what is the wavelength of the incident light on the metal in nanometers?
$$\left(\text{hc} = 1.24\ \text{eV}{\cdot}\mu\text{m}\ ,\ e = 1.6\times10^{-19}\ \text{C}\ ,\ m_e = 9\times10^{-31}\ \text{kg}\right)$$
(1) $480$ (2) $360$ (3) $240$ (4) $120$

178- The decay diagram of a proton-rich substance is shown below. What is the half-life of this substance in days?
[Figure: Graph of number of proton-rich nuclei (vertical axis: number of nuclei of proton-rich substance, with $N_0$ and $\frac{N_0}{16}$ marked) versus time in days (horizontal axis, with 22 marked). The curve is a decreasing exponential.]
\begin{flushright} (1) $12$
(2) $8$
(3) $6$
(4) $4$ \end{flushright}

179- If the distance between two point electric charges is decreased by 20 percent, by approximately what percent does the electric force between them decrease?
(1) $50$ (2) $30$ (3) $25$ (4) $15$

180- In a uniform electric field $E = 10^5\ \frac{\text{N}}{\text{C}}$, a particle with electric charge $q = -5\ \mu\text{C}$ moves along path $ABC$ from $A$ to $C$. How does the electric potential energy of the particle change along this path?
$$\left(\sin\alpha = 0.8\ ,\ AB = BC = 5\ \text{cm}\right)$$
[Figure: Uniform electric field $\vec{E}$ pointing to the right, with path ABC where A is on the left, B is in the middle, and C is at the bottom right, with angle $\alpha$ at B.]
\begin{flushright} (1) $0.1$ joule, increases
(2) $0.1$ joule, decreases
(3) $0.4$ joule, increases
(4) $0.4$ joule, decreases \end{flushright}
Calculation Space
%% Page 17 Physics $\leftarrow$ 122-A $\rightarrow$ Page 8A

181. In the figure below, the electric field vector at the vertex of an equilateral triangle in SI units is $\vec{E} = -2\times10^5\,\hat{i} - 1.8\times10^5\,\hat{j}$. The charges $q_1$ and $q_2$ are respectively how many microcoulombs? $\left(k = 9\times10^9\,\dfrac{\text{N}\cdot\text{m}^2}{\text{C}^2}\right)$
[Figure: Equilateral triangle with side 90 cm and height 40 cm; charge $q_1$ at top-right vertex, charge $q_2$ at bottom-left vertex, coordinate axes at bottom-right vertex]

• [(1)] $-4.8$ and $-6$
• [(2)] $4.8$ and $-6$
• [(3)] $-8$ and $-12.8$
• [(4)] $+8$ and $-12.8$

182. A capacitor with capacitance $5\,\mu\text{F}$ has air between its plates. We want to change the plate separation without changing the charge on the plates. When the capacitor is charged with an electric potential difference of 20 V, the energy stored in it is 2 millijoules. The dielectric coefficient of the insulator is how much?

• [(1)] $1.5$
• [(2)] $2$
• [(3)] $2.5$
• [(4)] $5$

183. In the circuit below, an ideal voltmeter reads 14 V. What is the potential difference across resistor $R$?
[Figure: Circuit with $\varepsilon_1 = 10\,\text{V}$, $r_1 = 2\,\Omega$, voltmeter $\text{V}$, resistor $R$, $r_2 = 1\,\Omega$, $\varepsilon_2 = 18\,\text{V}$]

• [(1)] $4$
• [(2)] $3$
• [(3)] $2$
• [(4)] $1$

184. In the figure below, all three resistors are identical. If we connect a switch and close it, the power consumed by the circuit changes to 9 watts. Each resistor is how many ohms?
[Figure: Circuit with three identical resistors (two in parallel, one in series) connected to a battery $\varepsilon = 18\,\text{V}$, with a switch]

• [(1)] $18$
• [(2)] $12$
• [(3)] $9$
• [(4)] $6$

%% Page 18 Physics $\leftarrow$ 122-A $\rightarrow$ Page 9

185. In the circuit below, the potential at point A is how many volts?
[Figure: Circuit with two batteries: $\varepsilon_1 = 18\,\text{V}$, $r_1 = 0.5\,\Omega$; $\varepsilon_2 = 12\,\text{V}$, $r_2 = 1.5\,\Omega$; external resistors $2\,\Omega$, $8\,\Omega$; $V_E = 0$]

• [(1)] $-22.75$
• [(2)] $-13.75$
• [(3)] $13.75$
• [(4)] $22.75$

186. The figure below shows part of an electrical circuit. The input power of the battery is how many watts?
[Figure: Circuit with battery $\varepsilon = 12\,\text{V}$, internal resistance $r = 3\,\Omega$, current $7\,\text{A}$]

• [(1)] $12$
• [(2)] $18$
• [(3)] $24$
• [(4)] $36$

187. At an altitude of about 3000 meters above sea level, the air pressure is $68\,\text{kPa}$. This pressure is how many centimeters of mercury?
$$\left(\text{density of mercury} = 13.6\,\frac{\text{g}}{\text{cm}^3},\quad g = 10\,\frac{\text{N}}{\text{kg}}\right)$$

• [(1)] $60$
• [(2)] $55$
• [(3)] $50$
• [(4)] $45$

188. Two moving objects A and B move in a straight path and in the same direction. Their collision is perfectly elastic. The kinetic energy of A equals 4 times the kinetic energy of B. If the mass of A is $2\,\text{kg}$, what is the mass of object B in kilograms?

• [(1)] $8$
• [(2)] $4$
• [(3)] $1$
• [(4)] $0.5$

189. Inside a fixed-volume capsule, one mole of nitrogen gas is placed and the air pressure is $\frac{5}{4}$ of atmospheric pressure. If we add helium gas to the tank and keep the temperature constant, the pressure inside the tank becomes how many times atmospheric pressure? (Molar mass of nitrogen gas and helium are 28 g/mol and 4 g/mol respectively.)

• [(1)] $10$
• [(2)] $9$
• [(3)] $4$
• [(4)] $2$

190. A gas inside a cylinder undergoes the cycle shown in the figure below. How many joules of heat does the gas absorb in this cycle?
[Figure: P-V diagram with a cycle. Points: A at $(1\,\text{L},\, 10^5\,\text{Pa})$, B at $(1\,\text{L},\, 3\times10^5\,\text{Pa})$, C at $(4\,\text{L},\, 3\times10^5\,\text{Pa})$, returning to A. Axes: $P\,(\text{Pa})$ vs $V\,(\text{L})$]

• [(1)] $500$
• [(2)] $450$
• [(3)] $300$
• [(4)] $150$

%% Page 19 Chemistry $\leftarrow$ 122-A $\rightarrow$ Page 10

191-- Which molecule has no triple bond?
(1) $O_2$ (2) $CO$ (3) $HCN$ (4) $N_2$

192-- Which of the following statements are correct?
A-- Bohr, based on the atomic model, was able to explain the line emission spectrum of elements.
B-- Each colored line in the line emission spectrum of elements has a specific energy and wavelength.
C-- Bohr, by studying the precise line emission spectrum of hydrogen, provided a model for atoms of elements.
D-- Scientists proposed a layered structure for atoms of elements to explain how atoms emit light.
(1) A, B (2) A, B, D (3) B, C (4) B, C, D

193-- Atom A has 8 electrons with $n=0$ and the number of its valence electrons equals the number of valence electrons of atom ${}_{31}\text{Ga}$. Element A is in the same group as which element in the periodic table?
(1) ${}_{47}\text{Ag}$ (2) ${}_{13}\text{Al}$ (3) ${}_{42}\text{Mo}$ (4) ${}_{39}\text{Y}$

194-- An athlete, during exercise, consumes 22 kilocalories of energy per minute. To provide the energy for one hour of exercise, if instead of the most suitable food, the least suitable food is used, how much of the least suitable food is needed?

Food	Combustion value (kJ$\cdot$g$^{-1}$)
A	11.5
B	25
C	18
D	4

(1) $6.5$ (2) $6$ (3) $5$ (4) $4.5$

195-- How many of the following statements are correct?

• Element ${}_{28}Z$ is a transition metal from group 15 and period 4 of the periodic table.
• In atoms of elements, subshells with $l+1$ are smaller and hold fewer electrons.
• If two nonmetals form a compound with general formula $\text{AD}_4$, element A is in group 14 of the periodic table.
• In the new atomic model, electrons in space are very small compared to the nucleus, and in the layers around it, they are considered to be taken.

(1) four (2) three (3) two (4) one
%% Page 20 Chemistry $\leftarrow$ 122-A $\rightarrow$ Page 11

196. In 10 grams of aluminum sulfide, approximately how many ions exist and what is the ratio of the mass of sulfur to aluminum in it? $(Al = 27, S = 32 : \text{g.mol}^{-1})$
$$\frac{32}{27} \ , \ 2\times10^{23} \quad (2) \qquad\qquad \frac{16}{9} \ , \ 2\times10^{23} \quad (1)$$ $$\frac{32}{27} \ , \ 4\times10^{22} \quad (4) \qquad\qquad \frac{16}{9} \ , \ 4\times10^{22} \quad (3)$$

197. If 0.15 mol of a cation from a divalent metal undergoes a complete reaction with phosphate anions and forms a compound with a mass of 13.1 grams, which metal does this cation belong to? $(O = 16, Mg = 24, P = 31, Ca = 40, Fe = 56, Zn = 65 : \text{g.mol}^{-1})$
Mg (4) Zn (3) Fe (2) Ca (1)

198. How many of the following statements are correct?

• Sharing electrons is a common property of metals and nonmetals.
• In general, metals and nonmetals have high reactivity and low reactivity, respectively.
• In a period of the periodic table, the metal with a lower atomic mass has more metallic character.
• In general, solid $p$-block elements in the periodic table are crystalline and have no smooth surfaces.
• Elements whose last two electrons are in the same subshell are in the same group of the periodic table.

(1) five (2) four (3) three (4) two

199. The concentration of calcium and magnesium ions ($\text{X}^{2+}$) in a hard water sample is 0.0025 molar and 264 ppm, respectively. If 27 grams of solid soap with a molar mass of $300\ \text{g.mol}^{-1}$ is added to 2.5 liters of this water sample, and considering that soap loses its cleaning ability by reacting with hard water ions and these $\text{Na}^+(\text{aq})$ ions exchange with $\text{Na}^+(\text{aq})$ ions, approximately how many grams of $\text{Na}^+(\text{aq})$ are needed in this process? (The mass of one gram per milliliter of water is considered from this sample.) $(Na = 23, Mg = 24 : \text{g.mol}^{-1})$
(Balanced reaction equation: $\text{RCOONa} + \text{XCl}_\gamma \rightarrow (\text{RCOO})_\gamma\text{X} + \text{NaCl}$)
(1) 0.78 , 75 (2) 1.55 , 75 (3) 1.55 , 25 (4) 0.78 , 25

200. The volume difference of 89.6 liters of the third member of the alkyne family and the same volume of the third member of the alkane family, both gases at STP conditions, with which hydrocarbon mass is equal? $(H = 1, C = 12 : \text{g.mol}^{-1})$
(1) ethane (2) ethyne
(3) second member of the alkane family (4) second member of the alkyne family
[Space for calculations]
%% Page 21 Chemistry $\leftarrow 122\text{-A} \rightarrow$ Page 12

201- The approximate graph of atomic radius variations ($r$) versus the main periodic table quantum number ($Z$) is shown below. Which statement about them is correct? (For noble gases, atomic radius is not defined.)
[Figure: Graph of atomic radius $r$ vs atomic number $Z$, showing peaks labeled A, C, E and troughs labeled B, D]

1. [(1)] D and E are in the halogens group.
2. [(2)] A and C are in the alkali metals group.
3. [(3)] B and D are in one period of the periodic table.
4. [(4)] A and B are in one group of the periodic table.