MikaStars39/nano-eval huggingface dataset:
The macroscopic fission cross-section of the reactor core is $5~ \mathbf{m}^{-1}$, and the power density is $20 \times 10^{6} \ \mathbf{W} / \mathbf{m}^{3}$. What is the average thermal neutron flux density inside the reactor core?

Options:
A. $$
1. 7 0 \times1 0^{1 7} \mathrm{m}^{2}
$$
B. $$
1. 4 0 \times1 0^{1 6} \mathrm{m}^{2}
$$
C. $$
1. 3 0 \times1 0^{1 7} \mathrm{m}^{2}
$$
D. $$
1. 1 5 \times1 0^{1 7} \mathrm{m}^{2}
$$
E. $$
1. 2 5 \times1 0^{1 7} \mathrm{m}^{2}
$$
F. $$
1. 6 0 \times1 0^{1 6} \mathrm{m}^{2}
$$
G. $$
1. 5 0 \times1 0^{1 6} \mathrm{m}^{2}
$$
H. $$
1. 9 5 \times1 0^{1 7} \mathrm{m}^{2}
$$
I. $$
1. 5 0 \times1 0^{1 7} \mathrm{m}^{2}
$$
J. $$
1. 8 0 \times1 0^{1 7} \mathrm{m}^{2}
$$
Answer: E
To obtain 1 kilowatt-hour of energy, what is the number of uranium-235 fissions required? How much mass of uranium-235 is needed to undergo fission?

Options:
A. $$
1. 200 {\times} 1 0^{16} ,~0. 3 4 {\times} 1 0^{-4} \, \text{g}
$$
B. $$
1. 125 {\times} 1 0^{17} ,~0. 4 3 {\times} 1 0^{-4} \, \text{g}
$$
C. $$
1. 100 {\times} 1 0^{17} ,~0. 5 0 {\times} 1 0^{-4} \, \text{g}
$$
D. $$
1. 110 {\times} 1 0^{17} ,~0. 5 5 {\times} 1 0^{-4} \, \text{g}
$$
E. $$
1. 180 {\times} 1 0^{16} ,~0. 3 9 {\times} 1 0^{-4} \, \text{g}
$$
F. $$
1. 150 {\times} 1 0^{17} ,~0. 6 2 {\times} 1 0^{-4} \, \text{g}
$$
G. $$
1. 135 {\times} 1 0^{17} ,~0. 4 2 {\times} 1 0^{-4} \, \text{g}
$$
H. $$
1. 130 {\times} 1 0^{17} ,~0. 4 7 {\times} 1 0^{-4} \, \text{g}
$$
I. $$
1. 140 {\times} 1 0^{16} ,~0. 7 0 {\times} 1 0^{-4} \, \text{g}
$$
J. $$
1. 250 {\times} 1 0^{16} ,~0. 8 6 {\times} 1 0^{-4} \, \text{g}
$$
Answer: B
The scattering cross sections of $H$ and $O$ over the energy range from 1000 eV to 1 eV are approximately constant, at 20 b and 38 b respectively. What are the $\xi$ for $H_2O$ and the average number of collisions required for neutrons in $H_2O$ to slow down from 1000 eV to 1 eV?

Options:
A. $$13.5$$
B. $$14.9$$
C. $$8.7$$
D. $$9.2$$
E. $$17.3$$
F. $$10.8$$
G. $$12.1$$
H. $$15.4$$
I. $$11.6$$
J. $$16.0$$
Answer: G
The distribution function of neutron density at position $x$ is
$$
n ( x, E, \overrightarrow{\Omega} )=\frac{n_{0}} {2 \pi} e^{-x / \lambda} e^{a E} ( 1+\cos \mu)
$$
where $\lambda$ and $a$ are constants, and $\mu$ is the angle between $\overrightarrow{\Omega}$ and the $x$-axis. What is the total neutron density $n(x)$?

Options:
A. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{c o s} \mu d \mu+\int_{0}^{\pi} \operatorname{s i n}^{2} \mu d \mu) $$
B. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n}^{2} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu\operatorname{s i n} \mu d \mu) $$
C. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {b} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu \operatorname{s i n} \mu d \mu) $$
D. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{b E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu\operatorname{s i n} \mu d \mu) $$
E. $$
n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu\operatorname{s i n} \mu d \mu)
$$
F. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s}^{2} \mu d \mu) $$
G. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{c o s} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu \operatorname{s i n} \mu d \mu) $$
H. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi/2} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu\operatorname{s i n} \mu d \mu) $$
I. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{e^{a E}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{c o s} \mu d \mu+\int_{0}^{\pi} \operatorname{s i n} \mu\operatorname{c o s} \mu d \mu) $$
J. $$ n ( x )=n_{0} e^{-x / \lambda} ( \frac{\ln{(e^{a E})}} {a} ) \Bigg|_{0}^{+\infty} ( \int_{0}^{\pi} \operatorname{s i n} \mu d \mu+\int_{0}^{\pi} \operatorname{c o s} \mu\operatorname{s i n} \mu d \mu) $$
Answer: E
The geometric curvature and neutron flux density distribution of a cuboid bare assembly with side lengths $a, \, b, \, c$ (including extrapolated distance). Assuming a cuboid bare assembly with side lengths $a = b = c = 0.5 \text{ m}$, $c = 0.6 \text{ m}$ (including extrapolated distance), $L = 0.0434 \text{ m, } \tau = 6 \text{ cm}^2$. If the power is $5000 \, \text{kW}, \ \ \Sigma_{\mathrm{f}} = 4.01 \, \text{m}^{-1}$, what is the neutron flux density distribution?

Options:
A. $$
4. 2 3 \times1 0^{1 8} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
B. $$
2. 0 1 2 \times1 0^{1 7} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
C. $$
6. 3 8 \times1 0^{1 9} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
D. $$
1. 0 0 7 \times1 0^{1 8} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
E. $$
1. 1 5 \times1 0^{1 9} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
F. $$
3. 4 9 \times1 0^{1 6} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
G. $$
5. 7 6 \times1 0^{1 8} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
H. $$
7. 5 4 \times1 0^{1 8} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
I. $$
9. 8 5 \times1 0^{1 7} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
J. $$
8. 9 1 \times1 0^{1 6} \,\mathrm{m}^{2} \cdot\mathrm{s}^{-1}
$$
Answer: D
During the startup of a nuclear reactor, when the boron concentration is $C_{\mathrm{B}} = 1500 \, \mathrm{ppm}$, the average counting rate is $n_{1}$, and it is known that the core's $k_{\mathrm{eff, 1}} = 0.97$. When the boron concentration is diluted to $C_{\mathrm{B}} = 1260 \, \mathrm{ppm}$, the average counting rate is $n_{2}$. If $n_{2} = 5n_{1}$, how much reactivity in pcm was introduced due to the boron dilution during this period?

Options:
A. $$2350.9~\mathrm{p c m}$$
B. $$2450.1~\mathrm{p c m}$$
C. $$2488.0~\mathrm{p c m}$$
D. $$2489.2~\mathrm{p c m}$$
E. $$2401.2~\mathrm{p c m}$$
F. $$2500.0~\mathrm{p c m}$$
G. $$2600.3~\mathrm{p c m}$$
H. $$2300.7~\mathrm{p c m}$$
I. $$2555.4~\mathrm{p c m}$$
J. $$2523.8~\mathrm{p c m}$$
Answer: D
In a certain pressurized water reactor system, when all the control rods are fully withdrawn at the beginning of the service life, $k_{\mathrm{eff}}=1.023$. When a certain group of control rods is inserted by 10 cm, $k_{\mathrm{eff}}=1.019$. What is the differential worth of this group of control rods?

Options:
A. $$
\mathrm{3 6. 7 ~ p c m / c m}
$$
B. $$
\mathrm{4 0. 8 ~ p c m / c m}
$$
C. $$
\mathrm{3 8. 4 ~ p c m / c m}
$$
D. $$
\mathrm{3 5. 0 ~ p c m / c m}
$$
E. $$
\mathrm{3 3. 9 ~ p c m / c m}
$$
F. $$
\mathrm{4 5. 2 ~ p c m / c m}
$$
G. $$
\mathrm{4 2. 0 ~ p c m / c m}
$$
H. $$
\mathrm{3 7. 2 ~ p c m / c m}
$$
I. $$
\mathrm{3 9. 1 ~ p c m / c m}
$$
J. $$
\mathrm{3 0. 5 ~ p c m / c m}
$$
Answer: C
In a pure water moderator, some boric acid $\mathrm{H_{3} B O_{3}}$ is added to increase the thermal neutron absorption cross-section by 10%. Given that the macroscopic thermal neutron absorption cross-section of water is $\Sigma_{\gamma\mathrm{k}}=0.0221 \, \mathrm{cm}^{-1}$, the microscopic thermal neutron absorption cross-section of boric acid is $\sigma_{\mathrm{anted}}=756 \, \mathrm{b}$, and the relative atomic mass of natural boron is $A_{\mathrm{B}}=10.82$. What is the boron concentration $C_{\mathrm{B}}$ in the moderator in ppm (1 ppm of boron concentration means 1 mg of natural boron per 1 kg of water)?

Options:
A. $$47.955~\mathrm{p p m}$$
B. $$59.342~\mathrm{p p m}$$
C. $$55.430~\mathrm{p p m}$$
D. $$52.524~\mathrm{p p m}$$
E. $$48.874~\mathrm{p p m}$$
F. $$45.782~\mathrm{p p m}$$
G. $$51.310~\mathrm{p p m}$$
H. $$53.198~\mathrm{p p m}$$
I. $$54.667~\mathrm{p p m}$$
J. $$60.115~\mathrm{p p m}$$
Answer: D
Consider a bare light water cylindrical reactor core with the nuclear parameters $L^{2}=4.7 \ \mathrm{cm}^{2}$, $\tau=48 \ \mathrm{cm}^{2}$, $\lambda_{\mathrm{tr}}=$ 9.7 cm, and post-boron addition $k_{\infty}=1.072$. Given that the core radius is $R=1.56 \ \mathrm{m}$, what is the reactivity of the core?

Options:
A. $$0.059$$
B. $$0.044$$
C. $$0.060$$
D. $$0.049$$
E. $$0.046$$
F. $$0.051$$
G. $$0.038$$
H. $$0.062$$
I. $$0.047$$
J. $$0.054$$
Answer: J
An ideal thermally driven refrigeration cycle receives thermal energy from a solar collector at a temperature of $70^{\circ}C$, provides cooling at $15^{\circ}C$, and discharges heat into the atmosphere at $35^{\circ}C$. Determine the thermodynamic coefficient of this system.

Options:
A. 1.3029
B. 1.5567
C. 1.8593
D. 2.3764
E. 0.9852
F. 2.0158
G. 0.7494
H. 1.2175
I. 1.0027
J. 1.4695
Answer: J
Calculate the minimum breakdown voltage of a uniform electric field air gap and the minimum value of the product of air pressure and gap distance. Given $A = 6460 / \mathrm{cm}, \, B = 1.9 \times 10^{5} \, \mathrm{V} / \mathrm{cm}, \, \gamma = 0.025^{\circ}$.
Analysis: For the following equation
$$
d A \delta \operatorname{exp} \Bigl( \frac{-B \delta}{E} \Bigr) = \operatorname{ln} \gamma^{-1}
$$
when self-sustained discharge occurs, $E$ reaches the breakdown field strength $E_{b}$, substituting $E_{b}=U_{b}/d$ into the equation and rearranging gives the breakdown voltage $U_{b}$ as
$$
U_{b} = \frac{d B \delta}{\operatorname{ln}(d A \delta / \operatorname{ln} \gamma^{-1})}
$$
$U_{b} = f(\delta d)$. To find the minimum value of this curve, differentiate with respect to $d$, set the derivative to zero, and we obtain
$(d \delta)_{\mathrm{min}} = \frac{e}{A} \operatorname{ln} \gamma^{-1}$.
At this point, $\operatorname{ln}(d A \delta / \operatorname{ln} \gamma^{-1}) = 1$, and the minimum value of $U_{b}$ is
$$
U_{\mathrm{bmin}} = B (d \delta)_{\mathrm{min}}
$$

Options:
A. $$
6. 9 1 5 4 ( \mathrm{k V} )
$$
B. $$
2. 9 4 5 0 ( \mathrm{k V} )
$$
C. $$
0. 5 8 3 9 ( \mathrm{k V} )
$$
D. $$
0. 2 9 4 5 ( \mathrm{k V} )
$$
E. $$
4. 0 7 6 2 ( \mathrm{k V} )
$$
F. $$
2. 3 4 8 7 ( \mathrm{k V} )
$$
G. $$
0. 0 8 2 1 ( \mathrm{k V} )
$$
H. $$
0. 7 6 8 3 ( \mathrm{k V} )
$$
I. $$
3. 5 9 1 8 ( \mathrm{k V} )
$$
J. $$
1. 1 2 3 4 ( \mathrm{k V} )
$$
Answer: D
The luminous atom is moving at a speed of $0.2c$ along the propagation direction of a certain light wave and resonates with this light wave. If the wavelength of this light wave is $\lambda=0.5 \mu \mathrm{m}$, find the rest central frequency of this luminous atom is___.

Options:
A. $$
5. 0 {\times} 1 0^{8} \, M H z
$$
B. $$
5. 5 {\times} 1 0^{8} \, M H z
$$
C. $$
3. 3 {\times} 1 0^{8} \, M H z
$$
D. $$
4. 2 {\times} 1 0^{8} \, M H z
$$
E. $$
4. 5 {\times} 1 0^{8} \, M H z
$$
F. $$
2. 4 {\times} 1 0^{8} \, M H z
$$
G. $$
5. 2 {\times} 1 0^{8} \, M H z
$$
H. $$
6. 0 {\times} 1 0^{8} \, M H z
$$
I. $$
3. 6 {\times} 1 0^{8} \, M H z
$$
J. $$
4. 8 {\times} 1 0^{8} \, M H z
$$
Answer: J
Calculate the peak emission cross-section $S_{32}$ in a YAG laser, given $\Delta \mathrm{v_F} = 2 \times 10^{11} \text{Hz}, \tau_3 = 2.3 \times 10^{-4} \text{s}, n = 1.8$. Answer is______.

Options:
A. $$
3. 3 \times 1 0^{-2 2} \, m^{2}
$$
B. $$
2. 5 \times 1 0^{-2 2} \, m^{2}
$$
C. $$
6. 2 \times 1 0^{-2 2} \, m^{2}
$$
D. $$
1. 9 \times1 0^{-2 2} \, m^{2}
$$
E. $$
1. 7 \times 1 0^{-2 2} \, m^{2}
$$
F. $$
1. 4 \times 1 0^{-2 2} \, m^{2}
$$
G. $$
2. 1 \times 1 0^{-2 2} \, m^{2}
$$
H. $$
5. 9 \times 1 0^{-2 2} \, m^{2}
$$
I. $$
4. 0 \times 1 0^{-2 2} \, m^{2}
$$
J. $$
7. 8 \times 1 0^{-2 2} \, m^{2}
$$
Answer: D
Helium-neon laser discharge tube has length of $l=0.5 \mathrm{m}$, and diameter of $\mathbf{d=1.5 \mathrm{mm}}$, with two reflectivities of $100\%$ and $98\%$, respectively. Other one-way loss rate is $0.015$, and the fluorescence linewidth is $\Delta V_{\mathrm{F}}=1500 \mathrm{MHz}$. Determine the number of intrinsic modes satisfying the threshold condition. $(\mathrm{G}_{\mathrm{m}}=3 \times 10^{-4} / \mathrm{d})$

Options:
A. 31
B. 22
C. 11
D. 16
E. 19
F. 25
G. 5
H. 28
I. 13
J. 8
Answer: J
He-Ne laser discharge tube pressure $\mathbf{p}=270 \mathbf{P} \mathbf{a}$, with upper and lower energy level lifetimes of $\tau_{3}=2 \times 10^{-8} \mathrm{s}$ and $\tau_{2}=2 \times 10^{-8} \mathrm{s}$, respectively. Find: ① the Doppler linewidth $\Delta\mathbf{v}_{\mathrm{D}}$ at $T=300K$; ② calculate the homogeneous linewidth $\Delta\mathbf{v}_{\mathrm{H}}$; ③ compute the intracavity light intensity ($\mathbf{I}_{s}=\mathbf{0.1 W/mm}^{2}$) when the hole burning width $\delta\mathsf{v=2 \Delta v_{H}}$.
Answer is___.

Options:
A. $$
1 7 0 0 M H z
$$
$$
2 2 5. 5 M H z
$$
$$
0. 1 w / m m^{2}
$$
B. $$
1 4 0 0 M H z
$$
$$
2 0 7. 5 M H z
$$
$$
0. 6 w / m m^{2}
$$
C. $$
1 3 0 0 M H z
$$
$$
2 1 0. 5 M H z
$$
$$
0. 3 w / m m^{2}
$$
D. $$
1 5 0 0 M H z
$$
$$
2 2 0. 5 M H z
$$
$$
0. 4 w / m m^{2}
$$
E. $$
1 6 0 0 M H z
$$
$$
2 1 5. 5 M H z
$$
$$
0. 7 w / m m^{2}
$$
F. $$
1 9 0 0 M H z
$$
$$
2 1 7. 5 M H z
$$
$$
0. 9 w / m m^{2}
$$
G. $$
1 0 0 0 M H z
$$
$$
2 3 1. 5 M H z
$$
$$
0. 8 w / m m^{2}
$$
H. $$
1 1 0 0 M H z
$$
$$
2 3 0. 5 M H z
$$
$$
0. 2 w / m m^{2}
$$
I. $$
1 8 0 0 M H z
$$
$$
2 0 8. 5 M H z
$$
$$
0. 6 w / m m^{2}
$$
J. $$
1 2 0 0 M H z
$$
$$
2 0 9. 5 M H z
$$
$$
0. 5 w / m m^{2}
$$
Answer: C
There is a plano-concave cavity with a cavity length of $L=30\text{cm}$, and the radii of curvature for the two mirrors are $\mathbf{R}_{1}=50\text{cm}$, $\mathbf{R}_{2}=30\text{cm}$. A He-Ne laser is used as the active medium. The focal parameter of the Gaussian beam produced by this cavity; the waist radius of the Gaussian beam produced by this cavity; the far-field divergence angle of the Gaussian beam produced by this cavity.
Answer is___.

Options:
A. $$
-4 0 c m,- 2 0 c m,
2 5 c m
$$
$$
0. 0 1 8 8 c m
$$
$$
1. 9 9 3 {\times} 1 0^{-3} r a d
$$
B. $$
-4 8 c m,- 1 2 c m,
2 2 c m
$$
$$
0. 0 1 7 7 c m
$$
$$
2. 2 5 5 {\times} 1 0^{-3} r a d
$$
C. $$
-4 5 c m,- 1 5 c m,
1 5 c m
$$
$$
0. 0 1 7 4 c m
$$
$$
2. 3 1 5 {\times} 1 0^{-3} r a d
$$
D. $$
-5 5 c m,- 1 0 c m,
1 0 c m
$$
$$
0. 0 1 5 0 c m
$$
$$
2. 0 0 5 {\times} 1 0^{-3} r a d
$$
E. $$
-7 5 c m,- 3 5 c m,
3 0 c m
$$
$$
0. 0 2 1 5 c m
$$
$$
3. 2 1 6 {\times} 1 0^{-3} r a d
$$
F. $$
-3 0 c m,- 2 2 c m,
1 8 c m
$$
$$
0. 0 1 6 9 c m
$$
$$
1. 7 8 6 {\times} 1 0^{-3} r a d
$$
G. $$
-6 0 c m,- 2 5 c m,
2 0 c m
$$
$$
0. 0 2 0 0 c m
$$
$$
3. 0 0 1 {\times} 1 0^{-3} r a d
$$
H. $$
-6 5 c m,- 1 8 c m,
1 1 c m
$$
$$
0. 0 1 6 3 c m
$$
$$
3. 0 7 0 {\times} 1 0^{-3} r a d
$$
I. $$
-5 0 c m,- 3 0 c m,
1 2 c m
$$
$$
0. 0 1 9 1 c m
$$
$$
2. 5 0 1 {\times} 1 0^{-3} r a d
$$
J. $$
-5 2 c m,- 2 8 c m,
1 6 c m
$$
$$
0. 0 1 8 5 c m
$$
$$
2. 4 5 9 {\times} 1 0^{-3} r a d
$$
Answer: C
There is a multi-longitudinal mode laser with 1,000 longitudinal modes. The cavity length of the laser is 1.5m, and the average output power is 1W, assuming the amplitudes of all longitudinal modes are equal. When using an acousto-optic loss modulation element for mode-locking, a voltage $V(t)=V_{m} \cos(\varpi_{m} t)$ is applied to the modulator. What is the frequency of the voltage?

Options:
A. $$
1 5 M H z
$$
B. $$
8 0 M H z
$$
C. $$
9 0 M H z
$$
D. $$
5 0 M H z
$$
E. $$
2 5 M H z
$$
F. $$
1 0 0 M H z
$$
G. $$
7 5 M H z
$$
H. $$
3 0 M H z
$$
I. $$
2 0 M H z
$$
J. $$
6 0 M H z
$$
Answer: D
When a certain luminous atom is stationary, it emits light with a wavelength of $0.488 \mu\mathrm{m}$. When it moves away from the observer at a speed of 0.2c, what does the observer perceive the wavelength of the emitted light to be?

Options:
A. $$
0. 4 9 0 2 \mu m
$$
B. $$
0. 6 1 2 7 \mu m
$$
C. $$
0. 4 7 5 9 \mu m
$$
D. $$
0. 4 8 8 0 \mu m
$$
E. $$
0. 5 8 5 6 \mu m
$$
F. $$
0. 5 9 5 8 \mu m
$$
G. $$
0. 5 6 7 2 \mu m
$$
H. $$
0. 4 1 0 3 \mu m
$$
I. $$
0. 5 7 0 6 \mu m
$$
J. $$
0. 6 0 0 0 \mu m
$$
Answer: E
In a certain digital communication system, a binary number is transmitted during communication. Due to channel noise, the receiving end cannot decode correctly. Let $X$ be the transmitted number and $Y$ be the decoded number. Suppose the probability of the transmitted number being 0 or 1 is
$$
P\{X=0\}=q=1-p, \quad P\{X=1\}=p
$$
Next, under the condition that the transmitted number is 0 or 1, let the conditional probability of the decoded number being 0 or 1 be
$$
\begin{array} {l}
{P(Y=0 \mid X=0) = p_{0}, \quad P(Y=1 \mid X=0) = q_{0} = 1-p_{0}} \\
{P(Y=0 \mid X=1) = 1-p_{1} = q_{1}, \quad P(Y=1 \mid X=1) = p_{1}} \\
\end{array}
$$
Find the probability of a decoding error occurring is ().

Options:
A. $$
q= p q_{1}+q p_{0}
$$
B. $$
q= q p_{1}+p q_{0}
$$
C. $$
q= p p_{0}+q p_{1}
$$
D. $$
p= q q_{0}+p q_{1}
$$
E. $$
q= p q_{0}+q q_{1}
$$
F. $$
q= q p_{0}+p p_{1}
$$
G. $$
p= p q_{0}+q q_{1}
$$
H. $$
p= q p_{0}+p q_{0}
$$
I. $$
p= q q_{1}+p q_{0}
$$
J. $$
p= p p_{0}+q p_{1}
$$
Answer: D
Let the number of independent trials $X$ follow a Poisson distribution with parameter $\lambda$, where the probability of success for each trial is $p$, and the probability of failure is $1-p$. Determine the probability distribution of the number of successful trials is ().

Options:
A. $$
Y \sim\mathrm{Bernoulli} ( \lambda p )
$$
B. $$
Y \sim\mathrm{P} ( \lambda (1-p) )
$$
C. $$
Y \sim\mathrm{P} ( \lambda p )
$$
D. $$
Y \sim\mathrm{Exp} ( \lambda p^2 )
$$
E. $$
Y \sim\mathrm{Geom} ( \frac{p}{1+\lambda} )
$$
F. $$
Y \sim\mathrm{P} ( \lambda^2 p )
$$
G. $$
Y \sim\mathrm{Norm} ( \lambda, p(1-p) )
$$
H. $$
Y \sim\mathrm{Hyper} ( n, \lambda p )
$$
I. $$
Y \sim\mathrm{Binom} ( n, \frac{\lambda}{1+\lambda} )
$$
J. $$
Y \sim\mathrm{Pois} ( n p (1-p) )
$$
Answer: C
Let $X(t) = \xi \cos(\beta t + \eta)$, where $\beta$ is a constant and the random variable $\xi$ follows a Rayleigh distribution $(\sigma > 0)$
$$f_\xi(x) = \begin{cases} \dfrac{x}{\sigma^2} \mathrm{e}^{-\frac{x^2}{2\sigma^2}}, & x > 0 \\ \\ 0, & x \leq 0 \end{cases}$$
Additionally, $\eta \sim U(0, 2\pi)$, and $\xi$ and $\eta$ are independent of each other. Find the mean function $m_{X}(t)$ and the covariance function $C_{X}(s, t)$ of the stochastic process $\left\{X(t), -\infty < t < +\infty\right\}$ is ().

Options:
A. $$
m(t)=\sigma
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\beta\cdot\operatorname{c o s} ( \sigma( s+t ) )}}}}} \\ \end{array}
$$
B. $$
m(t)=0
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\sigma\cdot\operatorname{s i n} ( \beta(s+t) )}}}}} \\ \end{array}
$$
C. $$
m(t)=0
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\beta^{2} \cdot\operatorname{s i n} ( \beta( s-t ) )}}}}} \\ \end{array}
$$
D. $$
m(t)=0
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\sigma^{2} \cdot\operatorname{c o s} ( \beta( s-t ) )}}}}} \\ \end{array}
$$
E. $$
m(t)=\sigma
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\pi\cdot\operatorname{c o s} ( \beta s t ) )}}}}} \\ \end{array}
$$
F. $$
m(t)=\pi
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\sigma^{2}\cdot\operatorname{s i n} ( \beta( s+t ) )}}}}} \\ \end{array}
$$
G. $$
m(t)=\pi
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\beta\cdot\operatorname{c o s} ( \sigma s t ) )}}}}} \\ \end{array}
$$
H. $$
m(t)=\sigma
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\sigma\cdot\operatorname{s i n} ( \beta( s+t ) )}}}}} \\ \end{array}
$$
I. $$
m(t)=\pi
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\beta\cdot\operatorname{c o s} ( \sigma( s-t ) )}}}}} \\ \end{array}
$$
J. $$
m(t)=0
$$
$$
\begin{array} {l} {{{{{C ( s, t )=\beta^{2} \cdot\operatorname{c o s} ( \sigma( s-t ) )}}}}} \\ \end{array}
$$
Answer: D
If a variable ellipsoidal surface
$$
\frac{x^{2}} {a^{2} k^{2} t^{4}}+k t^{2} \biggl( \frac{y^{2}} {b^{2}}+\frac{z^{2}} {c^{2}} \biggr)=1
$$
is the boundary surface of a fluid, where $k, a, b, c$ are constants, and $x, y, z$ are coordinates in the Cartesian coordinate system, The velocity components $u, v, w$ of the fluid on the boundary surface are ( ), ( ), and ( ), respectively.

Options:
A. $$\frac{x} {2t}$$
$$- \frac{2y} {t}$$
$$- \frac{2x} {t^{2}}$$
B. $$\frac{x} {t}$$
$$- \frac{y^{2}} {t}$$
$$- \frac{z} {2t}$$
C. $$\frac{x^2} {t}$$
$$- \frac{y} {t^2}$$
$$- \frac{2} {z}$$
D. $$\frac{2x} {t}$$
$$- \frac{2y} {t}$$
$$- \frac{z^{2}} {t}$$
E. $$\frac{x} {t}$$
$$- \frac{y} {2t}$$
$$- \frac{2z} {t}$$
F. $$\frac{2 x} {t}$$
$$- \frac{y} {t}$$
$$- \frac{z} {t}$$
G. $$\frac{x} {t}$$
$$- \frac{yt} {2^2}$$
$$- \frac{2z} {t}$$
H. $$\frac{x} {2t}$$
$$- \frac{y} {t^2}$$
$$- \frac{z} {t}$$
I. $$\frac{2x} {t^{2}}$$
$$- \frac{yt} {2}$$
$$- \frac{2z} {t}$$
J. $$\frac{x^{2}} {t}$$
$$- \frac{2y} {t^{4}}$$
$$- \frac{z} {t}$$
Answer: F
Given a temperature field
$$
T=\frac{A}{\sqrt{x^{2}+y^{2}+z^{2}}}+\frac{B}{\sqrt{(x+1)^{2}+y^{2}+z^{2}}},
$$
where $A$ and $B$ are constants, and the thermal conductivity coefficient is $K$. What is the direction in which the thermal conduction rate at point $(1, 1, 1)$ is the greatest ? What is the rate of thermal conduction in this direction ?

Options:
A. $$
( \sqrt{\ 2} \, A+2 B \,, \sqrt{\ 2} \, A+B \,, \sqrt{\ 2} \, A+B ) \,
$$
$$
K \sqrt{\frac{1} {6} [ ( \sqrt{2} A+2 B )^{2}+2 ( \sqrt{2} A+B )^{2} ]}
$$
B. $$
( 2 B \,, \sqrt{\ 2} \, A+a B \,, \sqrt{\ 2} \,, A+2 B ) \,
$$
$$
K \sqrt{\frac{1} {7} [ ( 2 B)^{2}+2 ( \sqrt{2} \, A+a B )^{2} ]}.
$$
C. $$
( 2 A+B \,, \sqrt{\ 2} \, A+2 B \,, \sqrt{\ 2} \, A+B ) \,
$$
$$
K \sqrt{\frac{1} {5} [ ( 2 A+B)^{2}+2 ( \sqrt{2} A+B )^{2} ]}.
$$
D. $$
( \sqrt{\ 2} \, A+B+a B \,, 2 B \,,\sqrt{\ 2} \, A ) \,
$$
$$
K \sqrt{\frac{1} {9} [ ( \sqrt{2} \, A+B+a B )^{2}+2 ( 2 B)^{2} ]}.
$$
E. $$
( \sqrt{\ 2} \, A+B \,, B+a A \,, \sqrt{\ 2} \, B+2 A ) \,
$$
$$
K \sqrt{\frac{1} {6} [ ( \sqrt{2} A+B )^{2}+2 ( B+a A )^{2} ]}.
$$
F. $$
( B+a A \,, \sqrt{\ 2} \, A+B \,, \sqrt{\ 2} \, A+2 B ) \,
$$
$$
K \sqrt{\frac{1} {4} [ ( B+a A)^{2}+2 ( \sqrt{2} A+B )^{2} ]}.
$$
G. $$
( \sqrt{\ 2} \, A+B \,, \sqrt{\ 2} \, B+a A \,, 2 B ) \,
$$
$$
K \sqrt{\frac{1} {5} [ ( \sqrt{2} A+B )^{2}+2 ( \sqrt{\ 2} \, B+a A )^{2} ]}.
$$
H. $$
( \sqrt{\ 2} \, A+B \,, 2 B \,, \sqrt{\ 2} \, A+2 B ) \,
$$
$$
K \sqrt{\frac{1} {7} [ ( \sqrt{2} A+B)^{2}+2 ( 2 B)^{2} ]}.
$$
I. $$
( \sqrt{\ 2} \, A \,, B+2 A \,, \sqrt{\ 2} \, B ) \,
$$
$$
K \sqrt{\frac{1} {6} [ ( \sqrt{2} A)^{2}+2 ( B+2 A)^{2} ]}.
$$
J. $$
( B \,, \sqrt{\ 2} \, A+2 B \,, \sqrt{\ 2} \, A+B ) \,
$$
$$
K \sqrt{\frac{1} {8} [ ( B)^{2}+2 ( \sqrt{2} A+2 B)^{2} ]}.
$$
Answer: A
A homogeneous sphere with a radius of $a$ is floating in a stationary liquid with a density of $\rho=\rho_{0} \left( 1+\beta h \right)$, where $h$ is the depth (distance to the liquid surface), $\beta$ is a constant, and $\rho_{0}$ is the density of the liquid at the surface. If the sphere has $\frac{27}{32}$ of its volume submerged below the liquid surface, the density of the sphere is().

Options:
A. $$\rho_{0} \cdot\frac{2 7} {3 2} \Big( 1+\frac{4} {8} \ \beta a \Big).
$$
B. $$\rho_{0} \cdot\frac{2 7} {3 4} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
C. $$\rho_{0} \cdot\frac{2 7} {3 2} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
D. $$\rho_{0} \cdot\frac{2 7} {2 8} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
E. $$\rho_{0} \cdot\frac{2 9} {3 2} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
F. $$\rho_{0} \cdot\frac{2 7} {3 2} \Big( 1+\frac{5} {6} \ \beta a \Big).
$$
G. $$\rho_{0} \cdot\frac{2 8} {3 2} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
H. $$\rho_{0} \cdot\frac{3 7} {3 2} \Big( 1+\frac{5} {8} \ \beta a \Big).
$$
I. $$\rho_{0} \cdot\frac{2 7} {3 2} \Big( 1+\frac{5} {9} \ \beta a \Big).
$$
J. $$\rho_{0} \cdot\frac{2 7} {3 2} \Big( 1+\frac{6} {8} \ \beta a \Big).
$$
Answer: C
Two coaxial horizontal cylinders with radii $a$ and $b$ $(a > b)$ are given, with the outer cylinder at rest and the inner cylinder moving with a constant axial speed $U$. Given that the axial pressure gradient $k_{0}$ of the fluid is constant, determine the laminar flow motion of the fluid of uniform density between these two cylinders.

Options:
A. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{2}+a^{1} ) \ \frac{\operatorname{l n} \frac{b} {r}} {\operatorname{l n} \frac{b} {a}}-( r^{2}-a^{1} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{a} {b}} \operatorname{l n} \frac{b} {r}.
$$
B. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{1}-a^{2} ) \ \frac{\operatorname{l n} \frac{r} {a}} {\operatorname{l n} \frac{b} {a}}-( r^{1}+a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{a} {b}} \operatorname{l n} \frac{b} {r}.
$$
C. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{1}-a^{2} ) \ \frac{\operatorname{l n} \frac{r} {b}} {\operatorname{l n} \frac{b} {a}}-( r^{2}+a^{1} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{b} {a}} \operatorname{l n} \frac{r} {a}.
$$
D. $$
-\frac{k_{0}} {4 \mu} \Biggl[ \ ( b^{2}-a^{2} ) \ \frac{\operatorname{l n} \frac{r} {a}} {\operatorname{l n} \frac{b} {a}}-( r^{2}-a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{b} {a}} \operatorname{l n} \frac{r} {b}
$$
E. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{1}+a^{2} ) \ \frac{\operatorname{l n} \frac{r} {b}} {\operatorname{l n} \frac{a} {b}}-( r^{1}-a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{b} {a}} \operatorname{l n} \frac{r} {a}.
$$
F. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{2}-a^{1} ) \ \frac{\operatorname{l n} \frac{r} {a}} {\operatorname{l n} \frac{a} {b}}-( r^{2}-a^{1} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{r} {b}} \operatorname{l n} \frac{a} {b}.
$$
G. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{2}-a^{1} ) \ \frac{\operatorname{l n} \frac{r} {b}} {\operatorname{l n} \frac{b} {a}}-( r^{1}+a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{a} {b}} \operatorname{l n} \frac{b} {r}.
$$
H. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{1}+a^{2} ) \ \frac{\operatorname{l n} \frac{b} {r}} {\operatorname{l n} \frac{a} {b}}-( r^{1}-a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{b} {a}} \operatorname{l n} \frac{r} {a}.
$$
I. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{1}-a^{2} ) \ \frac{\operatorname{l n} \frac{r} {a}} {\operatorname{l n} \frac{a} {b}}-( r^{2}-a^{1} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{r} {b}} \operatorname{l n} \frac{b} {a}.
$$
J. $$
-\frac{k_{b}} {4 \mu} \Biggl[ \ ( b^{2}-a^{1} ) \ \frac{\operatorname{l n} \frac{a} {r}} {\operatorname{l n} \frac{b} {a}}-( r^{1}+a^{2} ) \ \Biggr]+\frac{U} {\operatorname{l n} \frac{a} {b}} \operatorname{l n} \frac{b} {r}.
$$
Answer: D
A flow consists of three basic superimposed flows: a uniform flow $U$ along the positive $x$-axis, a point source with strength $2 \pi Q$ located at $z=0$, and a distributed system of point sinks with a total strength of $2 \pi Q$ continuously distributed from $z=a$ to $z=b$. Here, $a$ and $b$ are real numbers, and $b > a > 0$. Give the equation to determine the location of the stagnation point.

Options:
A. $$
U+\frac{Q} {z}-\frac{Q} {b-a} \operatorname{l n} \frac{z+b} {z-a}=0
$$
B. $$
U+\frac{Q} {z}-\frac{Q} {a-b} \operatorname{l n} \frac{z-b} {z-a}=0
$$
C. $$
U+\frac{Q} {z}-\frac{Q} {b} \operatorname{l n} \frac{z-a} {z-b}=0
$$
D. $$
U+\frac{Q} {z}+\frac{Q} {b-a} \operatorname{l n} \frac{z-a} {z-b}=0
$$
E. $$
U+\frac{Q} {x}-\frac{Q} {b-a} \operatorname{l n} \frac{x-a} {x-b}=0
$$
F. $$
U+\frac{Q} {z}-\frac{Q} {b-a} \operatorname{l n} \frac{z-a} {z-b}=0
$$
G. $$
U-\frac{Q} {z}-\frac{Q} {b-a} \operatorname{l n} \frac{z-a} {z-b}=0
$$
H. $$
U+\frac{Q} {z}-\frac{Q} {a-b} \operatorname{l n} \frac{z-a} {z-b}=0
$$
I. $$
U+\frac{Q} {y}-\frac{Q} {b-a} \operatorname{l n} \frac{y-a} {y-b}=0
$$
J. $$
U+\frac{Q} {z}-\frac{Q} {b-a} \operatorname{l n} \frac{a-z} {b-z}=0
$$
Answer: F
Consider linear gravity waves (cylindrical standing waves) inside a cylindrical container. Assume the radius of the container is $a$, and the water depth $h \gg a$. If the motion of the fluid in the container is axisymmetric, determine the possible standing wave frequencies of the fluid.

Options:
A. $$
\sqrt{g k_{n}}
$$
B. $$
\sqrt{g / k_{s}},
$$
C. $$
\sqrt{k_{s} / g},
$$
D. $$
\sqrt{g a h},
$$
E. $$
k_{s} \sqrt{g},
$$
F. $$
\sqrt{k_{s}^{2} g},
$$
G. $$
\sqrt{g h_{s}},
$$
H. $$
\sqrt{g h / a},
$$
I. $$
\sqrt{k_{s} h},
$$
J. $$
\sqrt{a g h},
$$
Answer: A
The order of crystallization ability from strongest to weakest for PE, PVC, and PVDC is ().

Options:
A. PVDC> PE> PE
B. PE> PVC> PE
C. PE> PVDC> PE
D. PVC> PVDC> PE
E. PE> PVC> PVDC
F. PE> PVDC >PVC
G. PVC> PE> PVC
H. PVDC> PE> PVC
I. PVC> PE> PVDC
J. PVDC> PVC> PE
Answer: F
The degree of polymerization of a polypropylene polymer chain is 600. Under $\theta$ conditions, the maximum stretch ratio of this polymer chain under external force is 10. Determine the limiting characteristic ratio $C_{\infty}$ of this polymer bond is ().It is known that the bond length of a $\mathrm{C-C}$ bond is $l=0.154$ nm, and the bond angle $\alpha=109^{\circ}28^{\prime}$.

Options:
A. 7.3
B. 7.8
C. 9.5
D. 6.4
E. 10.2
F. 12.4
G. 5.7
H. 8.9
I. 11.8
J. 8.1
Answer: J
The viscous flow activation energy of polyethylene is $E=23.4~\mathrm{kJ/mol}$. Try to calculate how much the temperature needs to be increased to reduce the viscosity by half at 150°C?

Options:
A. Approximately 60.3°C
B. Approximately 33.7°C
C. Approximately 49.2°C
D. Approximately 54.5°C
E. Approximately 51.5°C
F. Approximately 57.1°C
G. Approximately 44.8°C
H. Approximately 29.9°C
I. Approximately 46.2°C
J. Approximately 62.5°C
Answer: C
At temperature $\theta$, the relative molecular mass of the polymer is determined using the membrane osmotic pressure method. By plotting $\frac{\pi}{R T c}$ against $c$, the slope of the resulting line is obtained is ().

Options:
A. = 5
B. = -10
C. = 0
D. = 10
E. = 1
F. = 0.1
G. = 2
H. = 0.5
I. = -1
J. = -0.5
Answer: C
A rubber specimen at 25°C, with a stress of $1.5 \times 10^{6} \mathrm{~N/m^{2}}$, has an elongation ratio of 2.5. Calculate the stress required at 25°C when the elongation ratio is 1.5 is ().

Options:
A. $$
8. 2 9 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
B. $$
7. 3 3 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
C. $$
4. 6 8 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
D. $$
1. 9 9 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
E. $$
5. 0 2 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
F. $$
5. 8 0 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
G. $$
2. 4 5 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
H. $$
3. 5 4 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
I. $$
9. 1 1 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
J. $$
6. 7 6 \times1 0^{5} \mathrm{~ N / m^{2} ~}
$$
Answer: J
From the stress relaxation master curve of polyisobutylene, it is known that at 25°C, it takes 10 hours for the stress to relax to a modulus of $10^{6} ~ \mathrm{N/m}^{2}$. Try to calculate how long it will take for the stress to relax to the same modulus at -20°C is (). (Given that the glass transition temperature of polyisobutylene is $T_{\mathrm{g}}=-70°C$.)

Options:
A. 4398h
B. 5873h
C. 1023h
D. 2235h
E. 6149h
F. 1801h
G. 5248h
H. 3411h
I. 762h
J. 2976h
Answer: G
The melt viscosity of pseudoplastic fluids decreases with increasing shear stress is ().

Options:
A. Reduce
B. Invert
C. Maintain
D. Disperse
E. Isolate
F. Conserve
G. Exaggerate
H. Increase
I. Differentiate
J. Stabilize
Answer: A
If only considering the head-to-tail connection method, the number of possible isomers of polyisoprene is ().

Options:
A. Five types
B. Fourteen types
C. Twenty types
D. Nine types
E. Six types
F. Eleven types
G. Twelve types
H. Eight types
I. Ten types
J. Seven types
Answer: H
The $\theta$ temperature of polystyrene in a certain solvent is known to be $30^{\circ} \mathrm{C}$. At $30^{\circ} \mathrm{C}$, the osmotic pressure of polystyrene with a concentration of $1 \times 10^{-3} \mathrm{\ g / mL}$ in this solvent is measured to be 0.5140 g/cm. When the temperature is raised by 10°C, the measured osmotic pressure is 0.6637 g/cm. Try to calculate the second virial coefficient of polystyrene in this solvent at $40^{\circ} \mathrm{C}$ is ().

Options:
A. $1\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
B. $6\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
C. $7\times10^{-4}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
D. $2\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
E. $8\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
F. $1\times10^{-2}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
G. $4\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
H. $3\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
I. $9\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
J. $5\times10^{-3}\mathrm{~cm^3}\cdot\mathrm{mol/g^2}$
Answer: J
If only the head-to-tail linkage is considered, how many types does the configurations of polyolefins may have ( ).

Options:
A. Three types
B. Seven types
C. Nine types
D. Six types
E. Five types
F. Eleven types
G. Four types
H. Eight types
I. Ten types
J. Two types
Answer: E
Increasing the stretching rate, the measured modulus ().

Options:
A. The smaller it looks
B. The smoother it feels
C. The weaker it seems
D. The lighter it weighs
E. The bigger it is
F. The denser it appears
G. The more elastic it remains
H. The softer it gets
I. The less rigid it becomes
J. The thicker it appears
Answer: E
If the intermolecular forces of the polymer increase, then the tensile strength of the polymer ( ).

Options:
A. Weaken
B. Enlarge
C. Shrink
D. Diminish
E. Reduce
F. Compress
G. Contract
H. Minimize
I. Lower
J. Lesser
Answer: B
The deformation during the creep process of crosslinked polymers includes ().

Options:
A. Regular Deformation and Elastic Distortion
B. Typical Twisting and Elastic Tension Variation
C. Normal Warping and Maximum Elastic Strain
D. General Deviation and Flexible Distortion
E. Conventional Malformation and Elastic Displacement
F. Common Deflection and Superior Elastic Relaxation
G. Ordinary Deformation and High Elastic Deformation
H. Standard Bending and Elastic Contraction
I. Routine Contortion and Elevated Elastic Flexure
J. Usual Displacement and Elastic Compression
Answer: G
Approximate the pH value of a 0.2 mol/kg $H_{\mathrm{2}}$$SO_{\mathrm{4}}$ solution, given that the average activity coefficient of $H_{\mathrm{2}}$$SO_{\mathrm{4}}$ in this solution is 0.209 is().

Options:
A. $$
= 1. 0 8
$$
B. $$
= 4. 7 9
$$
C. $$
= 9. 8 6
$$
D. $$
= 3. 2 5
$$
E. $$
= 7. 4 4
$$
F. $$
= 0. 9 2
$$
G. $$
= 5. 1 1
$$
H. $$
= 2. 5 1
$$
I. $$
= 8. 3 0
$$
J. $$
= 6. 0 9
$$
Answer: A
At 25°C, the electromotive force of the battery Cd|Cd$C1_{\mathrm{2}}$(0.01 mol/dm$^{2}$), AgCl(solid)| Ag is 0.758 5 $\mathbf{V}$, with a standard electromotive force of 0.573 2 $\mathbf{V}$. The mean activity coefficient $\gamma_{\pm}$ in this CdCl2 solution is().

Options:
A. $$
\gamma_{\pm}=0. 6 2
$$
B. $$
\gamma_{\pm}=0. 5 1
$$
C. $$
\gamma_{\pm}=0. 7 1
$$
D. $$
\gamma_{\pm}=0. 3 9
$$
E. $$
\gamma_{\pm}=0. 4 3
$$
F. $$
\gamma_{\pm}=0. 7 9
$$
G. $$
\gamma_{\pm}=0. 5 8
$$
H. $$
\gamma_{\pm}=0. 4 7
$$
I. $$
\gamma_{\pm}=0. 6 8
$$
J. $$
\gamma_{\pm}=0. 5 5
$$
Answer: B
An organic compound undergoes electrolytic oxidation in a stationary solution at 25°C. If the diffusion step is the rate-controlling step, calculate the limiting diffusion current density for this electrode process. It is known that the number of electrons associated with each organic molecule is 4, the diffusion coefficient of the organic compound in the solution is $6 \times 10^{-5} \, \mathrm{cm}^{2} / \mathrm{s}$, the concentration is 0.1 mol/L, and the effective thickness of the diffusion layer is $5 \times 10^{-2} \, \mathrm{cm}$ is().

Options:
A. $$
= 0. 0 3 2 \, A / c m^{2}
$$
B. $$
= 0. 0 8 8 \, A / c m^{2}
$$
C. $$
= 0. 0 6 2 \, A / c m^{2}
$$
D. $$
= 0. 1 0 5 \, A / c m^{2}
$$
E. $$
= 0. 0 7 5 \, A / c m^{2}
$$
F. $$
= 0. 0 9 8 \, A / c m^{2}
$$
G. $$
= 0. 1 2 0 \, A / c m^{2}
$$
H. $$
= 0. 0 5 4 \, A / c m^{2}
$$
I. $$
= 0. 0 1 9 \, A / c m^{2}
$$
J. $$
= 0. 0 4 6 \, A / c m^{2}
$$
Answer: J
Consider a two-dimensional square lattice where each lattice point has an atom with mass $m$, accounting only for interactions between nearest neighbor atoms. The force constant is $\beta$, and the phonon dispersion relation is given by
$$
\omega_{v} = \sqrt{\frac{4 \beta}{m}} \left( \sin \left( \frac{q a}{2} \right) \right)
$$
In the long-wavelength limit, calculate the phonon density of states $D(\omega)$ as (), which is the number of lattice vibration modes per unit frequency interval $\mathrm{d}\omega$.

Options:
A. $$
\frac{\beta \omega} {2 \pi a^{2} S m}
$$
B. $$
\frac{S \beta \omega} {2 \pi a^{2} m}
$$
C. $$
\frac{S m \omega} {2 \pi a^{2} \beta}
$$
D. $$
\frac{S m \beta} {2 \pi a^{2} \omega}
$$
E. $$
\frac{2 S m \omega} {\pi a^{2} \beta}
$$
F. $$
\frac{S m \beta} {\pi a \omega}
$$
G. $$
\frac{S \omega} {2 \pi a^{2} m \beta}
$$
H. $$
\frac{\omega^{2} S m} {2 \pi a^{2} \beta}
$$
I. $$
\frac{S m \omega^{2}} {2 \pi a \beta}
$$
J. $$
\frac{S m \beta} {\pi a^{2} \omega}
$$
Answer: C
If silver is considered a monovalent metal with a spherical Fermi surface, calculate the Fermi energy and the Fermi temperature as ().

Options:
A. $$
6. 8 3 \mathrm{e V}
$$
$$5. 49 \times 10^{4}K$$
B. $$
3. 7 2 \mathrm{e V}
$$
$$8. 43 \times 10^{4}K$$
C. $$
5. 2 8 \mathrm{e V}
$$
$$6. 45 \times 10^{4}K$$
D. $$
6. 0 4 \mathrm{e V}
$$
$$7. 32 \times 10^{4}K$$
E. $$
3. 9 6 \mathrm{e V}
$$
$$7. 12 \times 10^{4}K$$
F. $$
4. 9 5 \mathrm{e V}
$$
$$5. 61 \times 10^{4}K$$
G. $$
4. 5 3 \mathrm{e V}
$$
$$7. 21 \times 10^{4}K$$
H. $$
5. 7 8 \mathrm{e V}
$$
$$6. 97 \times 10^{4}K$$
I. $$
6. 1 9 \mathrm{e V}
$$
$$5. 84 \times 10^{4}K$$
J. $$
5. 4 6 \mathrm{e V}
$$
$$6. 34 \times 10^{4}K$$
Answer: J
In the early days, semiconductor materials such as germanium and silicon were often assessed for purity by measuring their resistivity. If the resistivity measured at room temperature is 10Ω cm, estimate the purity of $N$-type germanium as ().
(Germanium electron mobility $\mu = 3900 \, \mathrm{cm}^{2} \mathrm{V}^{-1} \mathrm{s}^{-1}$, germanium atomic density $d = 4.42 \times 10^{22} \mathrm{cm}^{-3}$, electron charge $e = 1.6 \times 10^{-19} \mathrm{A} \cdot \mathrm{s}$)

Options:
A. $$ 8 8. \ \underbrace{8 8 8 8 8 8}_{6 \uparrow8} 5 3 \ \% $$
B. $$ 6 6. \ \underbrace{6 6 6 6 6 6}_{6 \uparrow6} 7 5 \ \% $$
C. $$
9 9. \ \underbrace{9 9 9 9 9 9}_{6 \uparrow9} 6 4 \ \%
$$
D. $$ 2 2. \ \underbrace{2 2 2 2 2 2}_{6 \uparrow2} 4 1 \ \% $$
E. $$ 4 4. \ \underbrace{4 4 4 4 4 4}_{6 \uparrow4} 9 8 \ \% $$
F. $$ 1 1. \ \underbrace{1 1 1 1 1 1}_{6 \uparrow1} 3 6 \ \% $$
G. $$ 7 7. \ \underbrace{7 7 7 7 7 7}_{6 \uparrow7} 5 9 \ \% $$
H. $$ 5 5. \ \underbrace{5 5 5 5 5 5}_{6 \uparrow5} 8 2 \ \% $$
I. $$ 0 0. \ \underbrace{0 0 0 0 0 0}_{6 \uparrow0} 5 4 \ \% $$
J. $$ 3 3. \ \underbrace{3 3 3 3 3 3}_{6 \uparrow3} 2 7 \ \% $$
Answer: C
Within an error range of 10, answer the following question using estimation, rough calculation, or memory. The de Broglie wavelength of the earth is ( ).

Options:
A. $$
2. 6 \times1 0^{-6 6} ( \mathbf{m} )
$$
B. $$
2. 8 \times1 0^{-6 1} ( \mathbf{m} )
$$
C. $$
4. 8 \times1 0^{-6 3} ( \mathbf{m} )
$$
D. $$
3. 7 \times1 0^{-6 3} ( \mathbf{m} )
$$
E. $$
3. 2 \times1 0^{-6 6} ( \mathbf{m} )
$$
F. $$
4. 2 \times1 0^{-6 2} ( \mathbf{m} )
$$
G. $$
4. 0 \times1 0^{-6 3} ( \mathbf{m} )
$$
H. $$
3. 5 \times1 0^{-6 5} ( \mathbf{m} )
$$
I. $$
5. 9 \times1 0^{-6 4} ( \mathbf{m} )
$$
J. $$
5. 1 \times1 0^{-6 4} ( \mathbf{m} )
$$
Answer: D
Find the limit of the sequence of functions defined on the real line
$$
\lim_{k \to\infty} \left( \lim_{j \to\infty} (\cos k! \pi x )^{2j} \right)
$$
is ().

Options:
A. x
B. 12
C. 2
D. 3
E. -1
F. 1
G. 0
H. pi
I. 4
J. 33
Answer: G
For the galaxy NGC 5585, the quantity $2 v_{r} / \operatorname{s i n} i=2 1 8 \operatorname{k m} s^{-1}$ ,and its apparent $H$ magnitude is $H=9. 5 5$ (already corrected for extinction). Use the Tully-Fisher method to determine what is the distance to this galaxy ?

Options:
A. $$
7. 9 3 \mathrm{~ M p c}
$$
B. $$
8. 3 2 \mathrm{~ M p c}
$$
C. $$
5. 7 4 \mathrm{~ M p c}
$$
D. $$
7. 3 1 \mathrm{~ M p c}
$$
E. $$
9. 2 0 \mathrm{~ M p c}
$$
F. $$
6. 8 7 \mathrm{~ M p c}
$$
G. $$
9. 6 5 \mathrm{~ M p c}
$$
H. $$
8. 9 8 \mathrm{~ M p c}
$$
I. $$
5. 9 0 \mathrm{~ M p c}
$$
J. $$
6. 5 2 \mathrm{~ M p c}
$$
Answer: D
The Einstein ring MG1654+ 1346 has a diameter of 2. $1^{\prime\prime}$ . The redshift of the source is $z=1. 7 4$ , and the redshift of the lensing galaxy is $z=0. 2 5$ . Estimate what is the mass of the lensing galaxy ?

Options:
A. $$
2. 5 \times1 0^{1 2} h^{-1} \ \mathrm{M}_{\odot}
$$
B. $$
4. 1 \times1 0^{1 1} h^{-1} \ \mathrm{M}_{\odot}
$$
C. $$
1. 3 \times1 0^{1 1} h^{-1} \ \mathrm{M}_{\odot}
$$
D. $$
5. 4 \times1 0^{1 0} h^{-1} \ \mathrm{M}_{\odot}
$$
E. $$
1. 0 \times1 0^{1 2} h^{-1} \ \mathrm{M}_{\odot}
$$
F. $$
8. 5 \times1 0^{1 0} h^{-1} \ \mathrm{M}_{\odot}
$$
G. $$
3. 3 \times1 0^{1 1} h^{-1} \ \mathrm{M}_{\odot}
$$
H. $$
6. 6 \times1 0^{1 2} h^{-1} \ \mathrm{M}_{\odot}
$$
I. $$
9. 8 \times1 0^{1 0} h^{-1} \ \mathrm{M}_{\odot}
$$
J. $$
7. 2 \times1 0^{1 2} h^{-1} \ \mathrm{M}_{\odot}
$$
Answer: C
Evaluate $\Omega_{m}, \Omega_{\mathrm{r e l}},$ and $\Omega_{\Lambda}$ at the time of decoupling ( $z=1 0 8 9$ ) using WMAP values.

Options:
A. $$0.95$$
$$0.05$$
$$2.1 \times1 0^{-9}$$
B. $$0.35$$
$$0.65$$
$$2.3 \times1 0^{-9}$$
C. $$0.75$$
$$0.25$$
$$1. 6 \times1 0^{-9}$$
D. $$0.85$$
$$0.15$$
$$1.8 \times1 0^{-9}$$
E. $$0.25$$
$$0.75$$
$$1.7 \times1 0^{-9}$$
F. $$0.05$$
$$0.95$$
$$1.5 \times1 0^{-9}$$
G. $$0.15$$
$$0.85$$
$$2.5 \times1 0^{-9}$$
H. $$0.55$$
$$0.45$$
$$1.4 \times1 0^{-9}$$
I. $$0.65$$
$$0.35$$
$$3.2 \times1 0^{-9}$$
J. $$0.45$$
$$0.55$$
$$1.9 \times1 0^{-9}$$
Answer: C
What is the total bolometric magnitude of the Galaxy?

Options:
A. $$
3. 6 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
B. $$
5. 0 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
C. $$
3. 6 \times1 0^{9} \mathrm{~ L_{\odot} ~}
$$
D. $$
4. 1 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
E. $$
3. 7 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
F. $$
3. 6 \times1 0^{1 1} \mathrm{~ L_{\odot} ~}
$$
G. $$
4. 2 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
H. $$
3. 0 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
I. $$
3. 5 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
J. $$
2. 8 \times1 0^{1 0} \mathrm{~ L_{\odot} ~}
$$
Answer: A
Estimate $d \Theta/ d R$ in the solar neighborhood, assuming that the Oort constants $A$ and $B$ are +14.8 and $- 1 2. 4$ km $\mathrm{s}^{-1}$ kpc, respectively. What does this say about the variation of?

Options:
A. $$
-4. 8 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
B. $$
-12. 4 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
C. $$
-2. 4 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
D. $$
-1. 2 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
E. $$
+9. 2 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
F. $$
-7. 6 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
G. $$
+6. 0 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
H. $$
+14. 8 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
I. $$
0. 0 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
J. $$
+2. 4 \; \mathrm{k m ~ s}^{-1} \; \mathrm{k p c}^{-1}.
$$
Answer: C
NGC 3091 has an effective radius of 10.07 kpc in the $B$ band and an average surface brightness within the effective radius of 21.52 $B$ -mag arcsec $- 2$ . From this information, determine $\mu_{e}$ in the $B$ band.

Options:
A. $$
2 1. 7 4 5
$$
B. $$
2 2. 6 8 9
$$
C. $$
2 0. 9 6 4
$$
D. $$
2 3. 1 2 0
$$
E. $$
2 1. 9 8 5
$$
F. $$
2 4. 5 7 1
$$
G. $$
2 4. 0 1 7
$$
H. $$
2 2. 9 1 3
$$
I. $$
2 3. 5 4 2
$$
J. $$
2 5. 3 0 8
$$
Answer: H
The Large Magellanic Cloud, which has a mass of about $2 \times1 0^{1 0} \mathrm{~ M_{\odot} ~}$ , orbits the Milky Way at a distance of 51 kpc. Assuming that the Milky Way's dark-matter halo and flat rotation curve extend out to the LMC, estimate how much time it will take for the LMC to spiral into the Milky Way (take $C=2 3$ ): (Note that the Small Magellanic Cloud may be gravitationally bound to the LMC, but its mass is an order of magnitude smaller; therefore, the SMC will be neglected in this problem.)

Options:
A. $$
3. 0 \mathrm{~ G y r}
$$
B. $$
2. 6 \mathrm{~ G y r}
$$
C. $$
3. 2 \mathrm{~ G y r}
$$
D. $$
1. 7 \mathrm{~ G y r}
$$
E. $$
2. 4 \mathrm{~ G y r}
$$
F. $$
1. 6 \mathrm{~ G y r}
$$
G. $$
2. 7 \mathrm{~ G y r}
$$
H. $$
1. 9 \mathrm{~ G y r}
$$
I. $$
3. 8 \mathrm{~ G y r}
$$
J. $$
2. 5 \mathrm{~ G y r}
$$
Answer: D
The following is the number of 8 displacement code machines $[x]_{\text{move}}$, when $[-x]_{\text{move}}$ ,() will overflow.

Options:
A. 00001111
B. 11001100
C. 11111111
D. 11110000
E. 00000000
F. 10000000
G. 00110011
H. 01010101
I. 10101010
J. 01111111
Answer: E
Let $x = -0.1101$, $y = 0.1011$. Using Booth's algorithm, find the value of $x \cdot y$ is ( ).

Options:
A. +0.1010
B. +0.1001
C. -0.0110
D. +0.0111
E. +1.0010
F. +0.1101
G. -0.1100
H. +1.0101
I. -1.0110
J. -1.0010
Answer: F
Let $x=+1 1 / 1 6$ and $y=+3 / 1 6$. Try using transformed two's complement to calculate $x+y$=().

Options:
A. 0.1100
B. 0.0101
C. 1.1110
D. 0.1101
E. 0.1110
F. 0.1010
G. 0.1111
H. 0.0110
I. 1.1101
J. 0.1000
Answer: E
When the CPU executes a program, the Cache completes 1,900 accesses, while main memory completes 100 accesses. Given that the Cache access cycle is 50ns and the main memory access cycle is 250ns, assuming the main memory and Cache are accessed simultaneously, what is the efficiency of the Cache/main memory system?

Options:
A. 80.0%
B. 90.5%
C. 88.9%
D. 86.4%
E. 76.2%
F. 83.3%
G. 79.2%
H. 81.5%
I. 82.1%
J. 85.7%
Answer: F
In a display adapter, the memory used to store display information is called the refresh memory, and its key performance indicator is bandwidth. In practical operations, multiple functional parts of the display adapter vie for the bandwidth of the refresh memory. Assuming that 50% of the total bandwidth is used for screen refresh, and 50% is reserved for other non-refresh functions, and operating at a resolution of 1024×768 pixels, a color depth of 3B, and a refresh rate of 72 Hz. Try calculating the total bandwidth of the refresh memory is ____.

Options:
A. 339.738MB/s (where $1 \mathbf{K}=1000)$
B. 285.634MB/s (where $1 \mathbf{K}=1 0 0 0 )$
C. 379.542MB/s (where $1 \mathbf{K}=1 0 0 0 )$
D. 312.678MB/s (where $1 \mathbf{K}=1 0 0 0 )$
E. 396.815MB/s (where $1 \mathbf{K}=1,000)$
F. 349.123MB/s (where $1 \mathbf{K}=1000$)
G. 367.489MB/s (where $1 \mathbf{K}=1,000)$
H. 290.731MB/s (where $1 \mathbf{K}=1000)$
I. 358.920MB/s (where $1 \mathbf{K}=1000 )$
J. 427.924MB/s (where $1 \mathbf{K}=1,000)$
Answer: A
There is a Cache system with a word length of 16 bits and main memory capacity of $16 \times 256$ blocks. The Cache has a capacity of $16 \text{ bit} \times 8$ blocks and uses fully associative mapping. If 5 blocks of information have already been loaded sequentially, what is the block number in the Cache that the main memory block containing word address 338H will be loaded into, and what is the word address in the Cache?

Options:
A. 011, 0010
B. 100, 0111
C. 101, 0100
D. 010, 0001
E. 010, 1010
F. 110, 1011
G. 000, 0110
H. 001, 1100
I. 111, 1110
J. 101, 1000
Answer: J
Assuming the instruction word length is 16 bits and the address code of the operand is 6 bits, the instructions come in three formats: zero-address, one-address, and two-address. Using extended opcode technology, if there are $P$ two-address instructions and $Q$ zero-address instructions, then what is the maximum type of one-address instructions?

Options:
A. $$
( 2^{4}-Q ) \times2^{6}
$$
B. $$
( 2^{3}-P ) \times2^{6}
$$
C. $$
( 2^{2}-Q ) \times2^{8}
$$
D. $$
( 2^{5}-P ) \times2^{4}
$$
E. $$
( 2^{4}-P ) \times2^{5}
$$
F. $$
( 2^{3}-P ) \times2^{7}
$$
G. $$
( 2^{4}-P ) \times2^{6}
$$
H. $$
( 2^{5}-Q ) \times2^{5}
$$
I. $$
( 2^{3}-Q ) \times2^{7}
$$
J. $$
( 2^{4}-P ) \times2^{7}
$$
Answer: G
The QPI bus is a point-to-point full-duplex synchronous serial bus, where devices on the bus can simultaneously receive and send information. Each direction can simultaneously transmit 20 bits of information (16 bits of data + 4 bits of parity). Each QPI data packet contains 80 bits of information, which are transmitted over 2 clock cycles, with 2 transmissions per clock cycle. Therefore, the QPI bus bandwidth is given by the number of transmissions per second × 2B × 2. If the QPI clock frequency is 2.4 GHz, then the bus bandwidth is ().

Options:
A. $$
1 6. 8 \mathrm{G B} / \mathrm{s}
$$
B. $$
1 9. 2 \mathrm{G B} / \mathrm{s}
$$
C. $$
2 3. 0 \mathrm{G B} / \mathrm{s}
$$
D. $$
1 7. 4 \mathrm{G B} / \mathrm{s}
$$
E. $$
1 8. 6 \mathrm{G B} / \mathrm{s}
$$
F. $$
2 0. 0 \mathrm{G B} / \mathrm{s}
$$
G. $$
2 1. 5 \mathrm{G B} / \mathrm{s}
$$
H. $$
1 8. 0 \mathrm{G B} / \mathrm{s}
$$
I. $$
1 5. 9 \mathrm{G B} / \mathrm{s}
$$
J. $$
2 2. 4 \mathrm{G B} / \mathrm{s}
$$
Answer: B
Assume the main frequency of the computer is 500 MHz, and the CPI is 4. There are devices $A$ and $\mathbf{B}$, with data transfer rates of 2 MB/s and 40 MB/s, respectively, and each corresponding I/O interface has a 32-bit data buffer register. If device B uses DMA mode, with each DMA transfer data block size being 1000 B, and the total clock cycles for CPU's DMA preprocessing and postprocessing are 500, then what is the maximum percentage of the CPU's total time that is used for input/output with device B?

Options:
A. 4%
B. 11%
C. 13%
D. 9%
E. 7%
F. 8%
G. 5%
H. 10%
I. 12%
J. 6%
Answer: A