152- A piece of lead is at a temperature of $20^\circ$C and has a volume. If we increase the temperature of this piece to $200^\circ$C, by what percentage does its volume increase? $$\left(\frac{1}{^\circ\text{C}} = 3\times10^{-5} = \text{coefficient of linear expansion of lead}\right)$$
(1) $0.6$ (2) $1.8$ (3) $6$ (4) $18$

153- According to the figure below, a straight wire of length $2.4\,\text{m}$ carries a current of $2.5\,\text{A}$ from east to west. The magnitude of Earth's magnetic field $G$ at the location of this wire is $0.5\,\text{G}$ and its direction is toward the north. Find the magnitude and direction of the magnetic force on this wire.
[Figure: magnetic field $\vec{B}$ directed into the page, current $I$ directed to the left]
(1) $3\times10^{-5}\,\text{N}$, upward (2) $3\times10^{-4}\,\text{N}$, upward
(3) $3\times10^{-5}\,\text{N}$, downward (4) $3\times10^{-4}\,\text{N}$, downward

154- The figure below shows the decay of nucleus 124. What is the name of the emitted particle?
[Figure: parent nucleus $\binom{71}{53}$ decays to daughter nucleus $\binom{72}{52}$ + $\cdots$]
(1) Alpha
(2) Gamma
(3) Positron
(4) Electron

155- The cross-sectional area of a string is $2\,\text{mm}^2$ and its density is $8\,\dfrac{\text{g}}{\text{cm}^3}$. If the wave propagation speed in the string is $25\,\dfrac{\text{m}}{\text{s}}$, what is the tension in the string in Newtons?
(1) $10$ (2) $20$ (3) $100$ (4) $200$

156- In the figure below, what is $V_2$ in volts?
[Figure: transformer circuit with $N_1=50$, $V_1=250\,\text{V}$, $N_2=400$, $V_2=?$, and resistance $R$]
(1) $216$
(2) $432$
(3) $2160$
(4) $4320$

Calculation Space
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157- Considering the positions of the magnetic poles in the figure below, which pole is point A, and what is the direction of the magnetic field at point M?
[Figure: Two magnetic pole configurations with arrows pointing right on both sides, field lines shown around point A in the center, and point M above]

• [(1)] $\rightarrow$ , S
• [(2)] $\leftarrow$ , S
• [(3)] $\rightarrow$ , N
• [(4)] $\leftarrow$ , N

158- A string with two fixed ends vibrates with frequencies $f_1 = 160\,\text{Hz}$, $f_p = 160\,\text{Hz}$, and $f_p = 320\,\text{Hz}$. $f_1 - f_p$ is how many hertz?
(1) $250$ (2) $180$ (3) $160$ (4) $80$

159- An alternating current whose peak value is $2\,\text{A}$ and its period is $0.025\,\text{s}$, passes through a $5\,\Omega$ resistor. What is the equation of the alternating current in SI?
(1) $I = 2\sin 400\pi t$ (2) $I = 2\sin 100\pi t$ (3) $I = 10\sin 400\pi t$ (4) $I = 10\sin 100\pi t$

160- A body slides on a smooth, inclined surface and comes down with constant velocity. Which of the following statements about this body is correct?
A- The work done by the normal force on the body is zero.
B- The mechanical energy of the body decreases.
C- The net force is equal to the weight.
D- The mechanical energy of the body remains constant.
(1) B (2) D (3) A and B (4) B and D

161- An ideal gas with volume 2 liters at constant pressure $P = 10^5\,\text{Pa}$ gives heat to the surroundings and its volume becomes $1.5$ liters. How many joules of work is done on the gas?
(1) $-50$ (2) $-30$ (3) $30$ (4) $50$

162- A particle with constant acceleration $\vec{a} = \left(4\dfrac{\text{m}}{\text{s}^2}\right)\hat{i}$ moves in the direction of the $x$-axis. If this particle covers 4 meters more distance in the third second than in the second second, what is the initial velocity in meters per second?
(1) $8$ (2) $6$ (3) $4$ (4) $2$
Calculation Space
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163. The figure below shows the velocity–time graph of a moving object along the $x$-axis. If the displacement in the time interval $t_1 = 28$ s up to $t_4 = 118$ s is equal to 176 meters, what is the velocity of the moving object at moment $t = 128$ s in meters per second?
[Figure: velocity-time graph $v(\text{m/s})$ vs $t(\text{s})$, with a triangular shape peaking between $t = 5$ and $t = 15$]

• [(1)] 3
• [(2)] 6
• [(3)] 8
• [(4)] 12

164. The position–time graph of a moving object with constant acceleration is shown below. The slope at moment $t = 8$ s is equal to $t = 8$ s. How much is the slope at moment $t = 2$ s?
[Figure: position-time graph $x$ vs $t(\text{s})$, curved line passing through points near $t = 4$ and $t = 10$]

• [(1)] 2
• [(2)] 3
• [(3)] 4
• [(4)] 5

165. The figure below shows the position–time graph of two moving objects A and B. For how many seconds is the distance between the two objects less than or equal to 20 meters?
[Figure: position-time graph $x(\text{m})$ vs $t(\text{s})$, showing two curves A and B; A starts higher around 200 m, B slightly lower; both curves intersect; graph shows values at 100, 200 on $y$-axis and $-200$ below origin, with $t = 10$ marked on $x$-axis]

• [(1)] 8
• [(2)] 6
• [(3)] 4
• [(4)] 2

166. A ball is released from height $h$ and falls with constant acceleration $g = 10\ \dfrac{\text{m}}{\text{s}^2}$. If the average velocity in the last $\dfrac{3}{4}$ of the path is $15\ \dfrac{\text{m}}{\text{s}}$, what is the average velocity over the entire path in meters per second?
$$15\ \frac{\text{m}}{\text{s}}$$

(1) $5$

(2) $7.5$

(3) $10$

(4) $12.5$

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167- A body of mass $20\,\text{kg}$ moves with constant velocity $\vec{v} = \left(5\dfrac{\text{m}}{\text{s}}\right)\hat{i}$ in a straight path. The net force is $\vec{F}_{\text{net}} = (4\text{N})\hat{i}$. For how many seconds does this force act on the body so that the impulse of the two becomes equal?
(1) $20$ (2) $25$ (3) $40$ (4) $50$

168- The force-time graph of a moving object is as shown below. The average net force exerted on the body during $50$ seconds of given data, how many Newtons is it?
[Figure: F(N) vs t(s) graph; F rises from 0 to 40 N between t=0 and t=10, stays at 40 N from t=10 to t=30, then decreases linearly to 0 at t=50]
(1) $15$ (2) $17.5$ (3) $14$ (4) $17.5$

169- In the figure below, the body is at rest on a horizontal surface. If we apply a horizontal force $F = 25\,\text{N}$ to it with a force gauge, how many Newtons does the surface exert on the body horizontally? $\left(g = 10\,\dfrac{\text{m}}{\text{s}^2}\right)$
[Figure: A block of mass $\rho\,\text{kg}$ connected to a force gauge with force $F$ applied horizontally; $\mu_s = 0.75$, $\mu_k = 0.4$]
(1) $95$ (2) $75$ (3) $15\sqrt{13}$ (4) $12\sqrt{29}$

170- A body of mass $5\,\text{kg}$ moves uniformly in a circular path, making $30$ revolutions per minute. If the radius of the path is $2$ meters, what is the kinetic energy of the body?
(1) $10\pi^2$ (2) $20\pi^2$ (3) $80$ (4) $40$

171- In an open space, the sound intensity level at a distance of $50$ meters from a sound source is $60$ decibels. How many milliwatts is the power of the source? $\left(I_0 = 10^{-12}\,\dfrac{\text{W}}{\text{m}^2},\ \pi = 3,\ \text{and energy absorbed by the medium is ignored.}\right)$
(1) $0.3$ (2) $6$ (3) $7.5$ (4) $30$
Calculation Space
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172. In the figure below, the surface of the spring is frictionless. The weight is pulled 3cm in the direction of the x-axis from the equilibrium position and released so that it performs simple harmonic motion. In the first half second, what is the distance traveled by the oscillator? $(\pi = \sqrt{10})$
$k = 50\,\dfrac{\text{N}}{\text{m}}$ $m = 200\,\text{g}$
[Figure: mass-spring system on frictionless horizontal surface with x-axis]

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

173. On a planet where the gravitational acceleration equals $g = \pi^2 \dfrac{\text{m}}{\text{s}^2}$, how many centimeters should we choose the length of a simple pendulum so that it completes one full oscillation every second?

• [(1)] 100
• [(2)] 75
• [(3)] 50
• [(4)] 25

174. A body of mass $m$ with a constant force of $5\,\dfrac{\text{N}}{\text{cm}}$ is connected to a spring of length 2cm. We pull and release the body on a frictionless horizontal surface. It starts oscillating. At the moment the oscillation speed reaches $\dfrac{\sqrt{2}}{2}$ of the maximum speed, how many joules is the mechanical energy of its translational motion?

• [(1)] 0.1
• [(2)] 0.2
• [(3)] 0.3
• [(4)] 0.4

175. In the figures below, the incoming rays include blue and red rays entering a glass from air. Which figure shows a physically possible refraction?
[Figure (1): rays labeled red and blue refracting at glass surface, red bending more]
[Figure (2): rays refracting at glass surface]
[Figure (3): rays labeled blue and red refracting at glass surface]
[Figure (4): rays labeled blue and red refracting at glass surface, blue bending more]
Calculation Space
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176- The energy of photon B is 25 percent less than the energy of photon A. If the difference in wavelength of these two photons is 50 nanometers, what is the frequency difference of these two photons? $\left(c = 3\times10^8\ \frac{\text{m}}{\text{s}}\right)$
(1) $5\times10^{14}$ (2) $2\times10^{14}$ (3) $2\times10^{13}$ (4) $5\times10^{13}$