MikaStars39/nano-eval huggingface dataset:
The artworks are in the form of sculptures or buildings which has Ancient Greek and Roman sources.It is the character of().

Options:
A. Romantic
B. Rococo
C. Modernist
D. Classic
E. Gothic
F. Baroque
G. Victorian
H. Neoclassical
I. Renaissance
J. Byzantine
Answer: D
The charge is uniformly distributed along a straight line segment of length $L$ with a linear density of $\eta$. What is the electric field strength at a point on the perpendicular bisector of the charged line that is at a distance $R$ from the line?

Options:
A. $$
E=\frac{\eta} {4 \pi\varepsilon_{0} L} \frac{L} {\sqrt{R^{2} - L^{2}}} e_{R}
$$
B. $$
E=\frac{\eta L} {4 \pi\varepsilon_{0} R} \frac{1} {\sqrt{R^{2}+L^{2}/4}} e_{R}
$$
C. $$
E=\frac{\eta} {2 \pi \varepsilon_{0} L} \frac{L R} {\sqrt{R^{2}+L^{2}}} e_{R}
$$
D. $$
E=\frac{\eta} {4 \pi\varepsilon_{0} R} \frac{L} {\sqrt{R^{2}+\frac{L^{2}} {4}}} e_{R}
$$
E. $$
E=\frac{\eta} {2 \pi\varepsilon_{0} R} \frac{L} {\sqrt{L^{2} + R^{2}}} e_{R}
$$
F. $$
E=\frac{\eta} {4 \pi R \varepsilon_{0}} \frac{2L} {\sqrt{R^{2}+L^{2}}} e_{R}
$$
G. $$
E=\frac{\eta R} {4 \pi\varepsilon_{0} L} \frac{L} {\sqrt{R^{2}+L^{2}}} e_{R}
$$
H. $$
E=\frac{\eta} {4 \pi L \varepsilon_{0}} \frac{R} {\sqrt{R^{2}+L^{2}/4}} e_{R}
$$
I. $$
E=\frac{\eta L} {4 \pi\varepsilon_{0} R^{2}} \frac{1} {\sqrt{R^{2} + L^{2}}} e_{R}
$$
J. $$
E=\frac{\eta} {2 \pi\varepsilon_{0} R} \frac{L} {\sqrt{R^{2} - L^{2}/4}} e_{R}
$$
Answer: D
There is a parallel plate capacitor with a plate spacing of 2.0 cm, containing a 1.0 cm thick piece of glass with a relative permittivity $\varepsilon_{\mathrm{r}}=7.0$ and a breakdown electric field strength of $25 \times 10^{6} \mathrm{~V/m}$. The rest of the space is filled with air, which has a breakdown field strength of $3 \times 10^{6} \mathrm{~V/m}$. Now, a voltage of 40 kV is applied across the plates. What is the electric field strength in the glass? If the glass is removed and the entire space between the plates is filled with air, what is the electric field strength in the air?

Options:
A. $$
0. 4 \times1 0^{6} \mathrm{~ V / m},\ 1.9 \times1 0^{6} \mathrm{~ V / m}
$$
B. $$
0. 3 \times1 0^{6} \mathrm{~ V / m},\ 2.6 \times1 0^{6} \mathrm{~ V / m}
$$
C. $$
0. 7 \times1 0^{6} \mathrm{~ V / m},\ 2.1 \times1 0^{6} \mathrm{~ V / m}
$$
D. $$
0. 8 \times1 0^{6} \mathrm{~ V / m},\ 2.2 \times1 0^{6} \mathrm{~ V / m}
$$
E. $$
1. 0 \times1 0^{6} \mathrm{~ V / m},\ 2.3 \times1 0^{6} \mathrm{~ V / m}
$$
F. $$
0. 6 \times1 0^{6} \mathrm{~ V / m},\ 1.8 \times1 0^{6} \mathrm{~ V / m}
$$
G. $$
0. 9 \times1 0^{6} \mathrm{~ V / m},\ 1.5 \times1 0^{6} \mathrm{~ V / m}
$$
H. $$
0. 2 \times1 0^{6} \mathrm{~ V / m},\ 2.4 \times1 0^{6} \mathrm{~ V / m}
$$
I. $$
0. 5 \times1 0^{6} \mathrm{~ V / m},\ 2 \times1 0^{6} \mathrm{~ V / m}
$$
J. $$
0. 5 \times1 0^{5} \mathrm{~ V / m},\ 2.5 \times1 0^{6} \mathrm{~ V / m}
$$
Answer: I
There are three resistors: 100 ohms, 1 kΩ, and 10 kΩ, each with a rated power of 0.25 W. Currently, these three resistors are connected in series. If the 1 kΩ resistor actually consumes 0.1 W of power, what is the relationship between the voltage across each resistor and its respective rated voltage?

Options:
A. $$
U_{1} < U_{\mathrm{1 H}}, U_{2} = U_{\mathrm{2 H}}, U_{3} < U_{\mathrm{3 H}}
$$
B. $$
U_{1} < U_{\mathrm{1 H}}, U_{2} > U_{\mathrm{2 H}}, U_{3} = U_{\mathrm{3 H}}
$$
C. $$
U_{1} = U_{\mathrm{1 H}}, U_{2} = U_{\mathrm{2 H}}, U_{3} < U_{\mathrm{3 H}}
$$
D. $$
U_{1} > U_{\mathrm{1 H}}, U_{2} = U_{\mathrm{2 H}}, U_{3} > U_{\mathrm{3 H}}
$$
E. $$
U_{1} = U_{\mathrm{1 H}}, U_{2} > U_{\mathrm{2 H}}, U_{3} = U_{\mathrm{3 H}}
$$
F. $$
U_{1} > U_{\mathrm{1 H}}, U_{2} < U_{\mathrm{2 H}}, U_{3} = U_{\mathrm{3 H}}
$$
G. $$
U_{1} > U_{\mathrm{1 H}}, U_{2} = U_{\mathrm{2 H}}, U_{3} < U_{\mathrm{3 H}}
$$
H. $$
U_{1} = U_{\mathrm{1 H}}, U_{2} < U_{\mathrm{2 H}}, U_{3} > U_{\mathrm{3 H}}
$$
I. $$
U_{1} < U_{\mathrm{1 H}}, U_{2} > U_{\mathrm{2 H}}, U_{3} < U_{\mathrm{3 H}}
$$
J. $$
U_{1} < U_{\mathrm{1 H}}, U_{2} < U_{\mathrm{2 H}}, U_{3} > U_{\mathrm{3 H}}
$$
Answer: J
In the series oscillating circuit, the inductor $L = 20 \, \text{mH}$ and the capacitor $C = 2.0 \, \mu \text{F}$, initially, there is a charge on $C$ but no current in $L$. What is the time $t_1$ required for the magnetic energy in $L$ to equal the electric energy in $C$ for the first time?

Options:
A. $$
1. 5 7 \times1 0^{-4} \mathrm{~ s}
$$
B. $$
0. 9 9 \times1 0^{-4} \mathrm{~ s}
$$
C. $$
1. 2 0 \times1 0^{-4} \mathrm{~ s}
$$
D. $$
3. 1 0 \times1 0^{-4} \mathrm{~ s}
$$
E. $$
1. 4 4 \times1 0^{-4} \mathrm{~ s}
$$
F. $$
2. 5 3 \times1 0^{-4} \mathrm{~ s}
$$
G. $$
1. 7 2 \times1 0^{-4} \mathrm{~ s}
$$
H. $$
2. 0 8 \times1 0^{-4} \mathrm{~ s}
$$
I. $$
1. 6 5 \times1 0^{-4} \mathrm{~ s}
$$
J. $$
2. 8 6 \times1 0^{-4} \mathrm{~ s}
$$
Answer: A
The working current of a fluorescent lamp labeled "220 V.15 W" is 0.35 A. If the power factor is increased to 0.9, what should be the size of the parallel capacitor $C_1$ and $C_2$?

Options:
A. $$
C_{1}=2. 8 \ \mu\mathrm{F} \,, \ C_{2}=6. 1 \ \mu\mathrm{F}
$$
B. $$
C_{1}=3. 8 \ \mu\mathrm{F} \,, \ C_{2}=6. 0 \ \mu\mathrm{F}
$$
C. $$
C_{1}=4. 0 \ \mu\mathrm{F} \,, \ C_{2}=5. 7 \ \mu\mathrm{F}
$$
D. $$
C_{1}=4. 3 \ \mu\mathrm{F} \,, \ C_{2}=5. 3 \ \mu\mathrm{F}
$$
E. $$
C_{1}=3. 5 \ \mu\mathrm{F} \,, \ C_{2}=4. 9 \ \mu\mathrm{F}
$$
F. $$
C_{1}=5. 2 \ \mu\mathrm{F} \,, \ C_{2}=4. 4 \ \mu\mathrm{F}
$$
G. $$
C_{1}=3. 6 \ \mu\mathrm{F} \,, \ C_{2}=5. 8 \ \mu\mathrm{F}
$$
H. $$
C_{1}=3. 2 \ \mu\mathrm{F} \,, \ C_{2}=5. 6 \ \mu\mathrm{F}
$$
I. $$
C_{1}=3. 9 \ \mu\mathrm{F} \,, \ C_{2}=6. 2 \ \mu\mathrm{F}
$$
J. $$
C_{1}=4. 1 \ \mu\mathrm{F} \,, \ C_{2}=5. 4 \ \mu\mathrm{F}
$$
Answer: D
Given the polarization intensity $P$, what is the depolarization field on the axis of an infinitely long cylindrical dielectric that is uniformly polarized along the vertical axis?

Options:
A. $$
-\frac{5P} {6 \, \varepsilon_{0}}
$$
B. $$
-\frac{P} {3 \, \varepsilon_{0}}
$$
C. $$
-\frac{P} {8 \, \varepsilon_{0}}
$$
D. $$
-\frac{P} {5 \, \varepsilon_{0}}
$$
E. $$
-\frac{2P} {5 \, \varepsilon_{0}}
$$
F. $$
-\frac{P} {2 \, \varepsilon_{0}}
$$
G. $$
-\frac{3P} {7 \, \varepsilon_{0}}
$$
H. $$
-\frac{P} {4 \, \varepsilon_{0}}
$$
I. $$
-\frac{P} {6 \, \varepsilon_{0}}
$$
J. $$
-\frac{7P} {9 \, \varepsilon_{0}}
$$
Answer: F
A coaxial line is composed of a long straight conductor and a coaxial cylinder around it. The radius of the conductor is $a$, the inner radius of the cylinder is $b$, and the outer radius is $c$. A current $I$ flows along the cylinder and returns along the conductor; the current distribution is uniform across their cross-sections. When $a=1.0 \, \mathrm{mm}$, $b=4.0 \, \mathrm{mm}$, $c=5.0 \, \mathrm{mm}$, and $I=10 \, \mathrm{A}$, how much magnetic energy is stored per meter length of the coaxial line?

Options:
A. $$
4. 3 \times1 0^{-5} \mathrm{J / m}
$$
B. $$
1. 7 \times1 0^{-5} \mathrm{J / m}
$$
C. $$
2. 6 \times1 0^{-5} \mathrm{J / m}
$$
D. $$
8. 2 \times1 0^{-5} \mathrm{J / m}
$$
E. $$
9. 4 \times1 0^{-5} \mathrm{J / m}
$$
F. $$
3. 9 \times1 0^{-5} \mathrm{J / m}
$$
G. $$
5. 8 \times1 0^{-5} \mathrm{J / m}
$$
H. $$
2. 0 \times1 0^{-5} \mathrm{J / m}
$$
I. $$
7. 1 \times1 0^{-5} \mathrm{J / m}
$$
J. $$
6. 5 \times1 0^{-5} \mathrm{J / m}
$$
Answer: B
How is the LUU-2 and LUU-19 flare initiated?

Options:
A. By turning the ignition lever
B. By pressing the launch button
C. By exerting pull on the lanyard
D. By activating the ignition switch
E. By rotating the control dial
F. By engaging the safety toggle
G. By applying downward force
H. By twisting the launch knob
I. By adjusting the fuse trigger
J. By pulling the safety pin
Answer: C
What is the function of the CXU 4A/B spotting charge?

Options:
A. It is utilized to improve aerodynamic stability of practice bomb BDU 45/B in air
B. It marks the impact point using smoke and sound for easy nighttime identification
C. It is used to increase the weight of practice bomb BDU 45/B for training purposes only
D. It is designed to enhance explosive yield and impact strength of BDU 45/B bombs
E. It is used with practice bomb BDU 45/B to provide a day time visual indication of bomb impact point and fuze function
F. It serves to illuminate the target area for laser-guided bomb operations
G. It makes the BDU 45/B practice bomb magnetic for naval mine countermeasures
H. It is integrated to deliver a real-time telemetry feed back to the training pilot
I. It modifies the explosive content for increased destructiveness of the BDU 45/B
J. It acts as a guidance system for the practice bomb BDU 45/B in flight
Answer: E
The illuminating candle in the LUU-2B/B aircraft parachute flare is made from what materials?

Options:
A. Magnesium, sodium nitrate, & a polymer binder
B. Aluminum, sodium chlorate, & an epoxy resin
C. Zinc, potassium perchlorate, & a silicone binder
D. Iron, ammonium nitrate, & a wax binder
E. Cobalt, magnesium perchlorate, & a rubber binder
F. Nickel, lithium chloride, & a latex binder
G. Copper, calcium nitrate, & a plastic binder
H. Silver, sodium bicarbonate, & a cellulose binder
I. Tin, ammonium perchlorate, & a polyester binder
J. Lead, barium nitrate, & an acrylic binder
Answer: A
What signal cartridge produces a flash of light & Large volumes of white smoke (for day use) when ignited?

Options:
A. MK 4 MOD 2
B. MK 4 MOD 1
C. MK 6 MOD 3
D. MK 3 MOD 5
E. MK 5 MOD 3
F. MK 5 MOD 1
G. MK 3 MOD 3
H. MK 2 MOD 3
I. MK 4 MOD 3
J. MK 4 MOD 5
Answer: I
When should the safety equipment of pyrotechnic & screening devices be removed?

Options:
A. During the design phase at the factory
B. Just before the device is launched
C. Before transporting the device to the site
D. After the device has been launched
E. When the device is initially assembled
F. When storing the device for future use
G. After the device has malfunctioned
H. Only during the cleaning process post-launch
I. Before any maintenance procedures begin
J. After the device has successfully functioned
Answer: B
A MK 25 marine location marker can be launched by which of the following methods?

Options:
A. Thermally or satellite transmitter
B. Mechanically or seabed projector
C. Automatic or aerial droplet
D. Manually or sonobuoy launcher
E. Ultrasonically or space module
F. Digitally or solar array
G. Electromagnetically or orbital launcher
H. Pneumatically or radio transceiver
I. Submerged or digital dispenser
J. Hydraulically or spray diffuser
Answer: D
What two types of composition material are used for infrared decoys?

Options:
A. Carbon fiber & light-sensitive alloy
B. Aluminum oxide & magnetic composite
C. Silicon carbide & acoustic polymer
D. Thermoplastic & photochromic paint
E. Nitrocellulose & luminescent film
F. Copper sulfate & pressure-sensitive tape
G. Pyrotechnic & pyrophoric metal
H. Fiber optic glass & chemically-reactive gel
I. Polyester resin & electrostatic coating
J. Graphite blend & fluorescent dye
Answer: G
If longitudes of A and B are given as 32°12' W, 44°2' having a latitude of 29°24', what is the distance in km between the points A and B?

Options:
A. 82.7km
B. 36.4km
C. 27.0km
D. 73.6km
E. 19.54km
F. 19.1km
G. 91.1km
H. 42.3km
I. 11.9km
J. 58.2km
Answer: F
A spiral galaxy is observed to have a rotation curve that can be well fitted by the following\nanalytic expression:
$$v ( R )=200( 1-e^{-R / R_{0}}) \mathrm{k m / s e c} $$,
where $e^{-R / R_{0}}$ is an exponential function of $R$, the radial distance from the center of the galaxy, and $R_{0}$ is a constant whose value is 4 kpc. (Assume that the galaxy is viewed edge-on so that the maximum Doppler velocities are observed.)
How much mass is there interior to a distance of 16 kpc from the center? (Express your answer in units of $M_{\\⊙}$)

Options:
A. 6×10¹¹$M_{⊙}$
B. 8×10¹¹$M_{⊙}$
C. 10¹⁰$M_{⊙}$
D. 9×10¹¹$M_{⊙}$
E. 10¹¹$M_{\\⊙}$
F. 7×10¹¹$M_{⊙}$
G. 4×10¹¹$M_{⊙}$
H. 3×10¹¹$M_{⊙}$
I. 5×10¹¹$M_{⊙}$
J. 10¹²$M_{⊙}$
Answer: E
$\mathbf{A}$ pure He star with mass equal to 1 $M_{\odot}$ has a radius of 0.2 $R_{\odot}$ , a central density, $\rho_{c}=1 0^{4}$ $\mathrm{g} ~ \mathrm{c m}^{-3}$ (or $1 0^{7}$ kg $\mathrm{m}^{-3}$ ), and a central temperature of $T_{c}=1. 3 2 \times1 0^{8}$ K. It is in thermal equilibrium, which means that the nuclear luminosity generated in the interior equals the luminosity radiated from the surface. Consider all the He burning to take place in the central 10%, by mass, of the star, and no burning to occur outside this region. Further, assume that the density and temperature throughout the nuclear burning region are constant at $\rho_{c}$ and $T_{c}$. The energy released per gram per second from He burning is given by the expression:
$$\mathcal{E} ( \rho, T ) \simeq4 \times1 0^{1 1} \rho^{2} T_{8}^{-3} \operatorname{e x p} [-4 2. 9 / T_{8} ] \mathrm{\\ \\ e r g s ~\\ g m^{-1} \\ s e c^{-1} \\ \\}.$$
For all mks units (including $\rho$ ) simply take the leading coefficient to be 40 rather than $4 \times1 0^{1 1}$.
The reaction that powers this star is $3_{2} H e^{4} \to_{6} C^{1 2}+\gamma$. The atomic mass excess of a ${}_{2} H e^{4}$ atom is 2.42 MeV and that of a ${}_{6}C^{1 2}$ atom is 0 MeV. Find the time for all the helium in the core of the star (i.e., the central 10% by mass) to be burned to carbon.

Options:
A. $$1. 5 \times1 0^{5} \mathrm{~ y e a r s}$$
B. $$1. 2 \times1 0^{5} \mathrm{~ y e a r s}$$
C. $$1. 0 \times1 0^{5} \mathrm{~ y e a r s}$$
D. $$1. 6 \times1 0^{5} \mathrm{~ y e a r s}$$
E. $$1. 3 \times1 0^{5} \mathrm{~ y e a r s}$$
F. $$1. 4 \times1 0^{5} \mathrm{~ y e a r s}$$
G. $$1. 1 \times1 0^{5} \mathrm{~ y e a r s}$$
H. $$1. 9 \times1 0^{5} \mathrm{~ y e a r s}$$
I. $$1. 8 \times1 0^{5} \mathrm{~ y e a r s}$$
J. $$1. 7 \times1 0^{5} \mathrm{~ y e a r s}$$
Answer: E
Recent measurements find that the Oort A and Oort B coefficients for our Galaxy are 14 km $\mathrm{s e c}^{-1} ~\mathrm{k p c}^{-1}$ and - 12 km $\mathrm{s e c}^{-1} ~\mathrm{k p c}^{-1}$, respectively. (Recall that $A \equiv-\frac{1} {2} R ( d \omega/ d R )$ and $B \equiv A-\omega.$)
Use the above values of A and B to find the rotation frequency (or period) of the Sun around the Galaxy.

Options:
A. 290 million years
B. 280 million years
C. 240 million years
D. 210 million years
E. 230 million years
F. 270 million years
G. 260 million years
H. 200 million years
I. 220 million years
J. 250 million years
Answer: J
Find the gravitational acceleration due to the Sun at the location of the Earth's orbit (i.e., at a distance of 1 AU).

Options:
A. $$0. 0 9 1 ~\mathrm{m / s}^{2}$$
B. $$0. 0 0 6 ~\mathrm{m / s}^{2}$$
C. $$0. 0 2 1 ~\mathrm{m / s}^{2}$$
D. $$0. 1 2 0 ~\mathrm{m / s}^{2}$$
E. $$0. 0 7 5 ~\mathrm{m / s}^{2}$$
F. $$0. 0 5 8 ~\mathrm{m / s}^{2}$$
G. $$0. 0 3 2 ~\mathrm{m / s}^{2}$$
H. $$0. 0 4 4 ~\mathrm{m / s}^{2}$$
I. $$0. 0 8 2 ~\mathrm{m / s}^{2}$$
J. $$0. 1 1 3 ~\mathrm{m / s}^{2}$$
Answer: B
In a certain region, the total sales revenue for washing machine products for the entire year of 2010 was 80 million yuan. If a washing machine manufacturing company had sales of 120,000 yuan in the first half of the year, what would be the company's market share?

Options:
A. 0.8%
B. 1.5%
C. 0.5%
D. 0.7%
E. 0.4%
F. 3%
G. 0.3%
H. 0.2%
I. 0.15%
J. 0.6%
Answer: G
Which electrode can be used to pick up signals from individual fibers of muscle tissues?

Options:
A. transdermal surface electrode
B. insulated wire loop electrode
C. monopolar needle electrode
D. intramuscular patch electrode
E. dual-channel probe electrode
F. adhesive gel grid electrode
G. bipolar needle electrode
H. multi-element needle electrode\
I. grounded ring disc electrode
J. concentric core needle electrode
Answer: H
In typical proton NMR imaging experiments, RF pulse lengths $( Φ_{{t i p}}=$ 90°) are 1000 μsec. How big is B₁?

Options:
A. B₁ = 2.00 x 10⁻⁶ T
B. B₁ = 8.32 x 10⁻⁶ T
C. B₁ = 1.29 x 10⁻⁶ T
D. B₁ = 6.94 x 10⁻⁶ T
E. B₁ = 2.57 x 10⁻⁶ T
F. B₁ = 9.23 x 10⁻⁶ T
G. B₁ = 4.67 x 10⁻⁶ T
H. B₁ = 7.45 x 10⁻⁶ T
I. B₁ = 3.18 x 10⁻⁶ T
J. B₁ = 5.81 x 10⁻⁶ T
Answer: J
A patient died of heart failure. The hospital diagnosis was rheumatic heart disease with mitral stenosis and insufficiency. The autopsy revealed a spherical, dark red and grayish-white mass in the enlarged left atrium, likely a ().

Options:
A. Mitral prolapse
B. Giant cell tumor
C. Atrial myxoma
D. Myxomatous tumor
E. Blood clot
F. Red thrombus
G. Mixed thrombus
H. Cardiac sarcoma
I. White thrombus
J. Hyaline thrombus
Answer: G
The patient, a 5-year-old child, presents with weakness in the lower limbs, difficulty climbing stairs, and a tendency to push their backside out when rising to stand. A muscle biopsy revealed variability in skeletal muscle fiber size, necrosis of some muscle cells, and interstitial fibrosis. The possible disease is ().

Options:
A. Congenital myopathy
B. Mmyodystrophy
C. Mitochondrial myopathy
D. Spinal muscular atrophy
E. Myasthenia gravis
F. Becker muscular dystrophy
G. Polymyositis
H. Amyotrophic lateral sclerosis
I. Guillain-Barré syndrome
J. Peripheral neuropathy
Answer: B
The symbol set of a certain information source consists of A, B, C, D, and E. Assume each symbol appears independently, with their appearance probabilities being 1/4, 1/8, 1/8, 3/16, and 5/16, respectively. Find the average information content of this information source's symbols.

Options:
A. $$
2. 0 2 \mathrm{b i t} /symbol
$$
B. $$
1. 2 6 \mathrm{b i t} /symbol
$$
C. $$
0. 7 4 \mathrm{b i t} /symbol
$$
D. $$
0. 9 3 \mathrm{b i t} /symbol
$$
E. $$
1. 6 1 \mathrm{b i t} /symbol
$$
F. $$
1. 4 7 \mathrm{b i t} /symbol
$$
G. $$
1. 5 8 \mathrm{b i t} /symbol
$$
H. $$
1. 0 5 \mathrm{b i t} /symbol
$$
I. $$
2. 2 3 \mathrm{b i t} /symbol
$$
J. $$
1. 8 9 \mathrm{b i t} /symbol
$$
Answer: I
To use a 7-bit Barker code as a group synchronization code, with a bit error rate of $1 \times 10^{-4}$, find the probability of synchronization loss when the allowable number of error codes is 0 and 1, respectively.

Options:
A. $$
2. 0 9 9 3 \times1 0^{-7}
$$
B. $$
1. 3 4 6 8 \times1 0^{-7}
$$
C. $$
2. 1 0 5 6 \times1 0^{-7}
$$
D. $$
3. 1 4 0 9 \times1 0^{-7}
$$
E. $$
1. 9 2 3 7 \times1 0^{-7}
$$
F. $$
3. 6 3 2 1 \times1 0^{-7}
$$
G. $$
2. 2 9 9 1 \times1 0^{-7}
$$
H. $$
1. 5 8 7 1 \times1 0^{-7}
$$
I. $$
2. 5 0 8 4 \times1 0^{-7}
$$
J. $$
2. 7 4 8 5 \times1 0^{-7}
$$
Answer: A
There are 60 analog voice channels transmitted using frequency division multiplexing. It is known that the frequency range of each voice channel is $0 \sim 4 \mathrm{kHz}$ (including the guard band), with the subcarrier using SSB modulation and the main carrier using FM modulation, and the modulation index $m_{f}=2$. Determine the bandwidth of the channel transmission signal.

Options:
A. $$
1. 5 6 \mathrm{M H z}
$$
B. $$
1. 2 8 \mathrm{M H z}
$$
C. $$
1. 3 6 \mathrm{M H z}
$$
D. $$
1. 4 0 \mathrm{M H z}
$$
E. $$
1. 4 4 \mathrm{M H z}
$$
F. $$
1. 5 0 \mathrm{M H z}
$$
G. $$
1. 4 8 \mathrm{M H z}
$$
H. $$
1. 3 2 \mathrm{M H z}
$$
I. $$
1. 2 2 \mathrm{M H z}
$$
J. $$
1. 6 0 \mathrm{M H z}
$$
Answer: E
Using the 2FSK method to transmit binary digits over a transmission channel with an equivalent bandwidth of $2400 Hz$. The frequencies of the 2FSK signals are \( $f_{1} = 980 \, \text{Hz}$ \) and \( $f_{2} = 1580 \, \text{Hz}$ \), with a symbol rate \( $R_{B} = 300 \, \text{Baud}$ \). The signal-to-noise ratio at the input of the receiver (i.e., at the output of the channel) is 6 dB. Find the bit error rate of the system when demodulating using envelope detection.

Options:
A. $$
2. 1 \times1 0^{-7}
$$
B. $$
7. 4 \times1 0^{-8}
$$
C. $$
2. 3 \times1 0^{-3}
$$
D. $$
9. 8 \times1 0^{-3}
$$
E. $$
4. 9 \times1 0^{-2}
$$
F. $$
8. 6 \times1 0^{-1}
$$
G. $$
1. 7 \times1 0^{-4}
$$
H. $$
1. 0 \times1 0^{-5}
$$
I. $$
3. 2 \times1 0^{-6}
$$
J. $$
5. 5 \times1 0^{-4}
$$
Answer: G
The voice signal with a maximum frequency of 4 kHz, encoded with 13-segment A-law PCM, has a transmission rate of ____ after encoding.

Options:
A. $$
5 0 \mathrm{k b i t} / \mathrm{s}
$$
B. $$
7 6 \mathrm{k b i t} / \mathrm{s}
$$
C. $$
5 6 \mathrm{k b i t} / \mathrm{s}
$$
D. $$
4 8 \mathrm{k b i t} / \mathrm{s}
$$
E. $$
6 0 \mathrm{k b i t} / \mathrm{s}
$$
F. $$
6 4 \mathrm{k b i t} / \mathrm{s}
$$
G. $$
7 2 \mathrm{k b i t} / \mathrm{s}
$$
H. $$
6 8 \mathrm{k b i t} / \mathrm{s}
$$
I. $$
5 2 \mathrm{k b i t} / \mathrm{s}
$$
J. $$
8 0 \mathrm{k b i t} / \mathrm{s}
$$
Answer: F
The analog signal $m(t)$, known to have a maximum frequency of 4 kHz, follows a uniform distribution within a quantization range of $(+1, 0 \sim -1.0)$V. If a PCM system is used for sampling, uniform quantization, and encoding, the question is: To achieve a quantization signal-to-noise ratio greater than 30 dB, what should be the quantization interval of the uniform quantizer?

Options:
A. $$
0. 1 0 0 \mathrm{V}
$$
B. $$
0. 0 9 8 \mathrm{V}
$$
C. $$
0. 0 7 5 \mathrm{V}
$$
D. $$
0. 0 8 3 \mathrm{V}
$$
E. $$
0. 1 1 0 \mathrm{V}
$$
F. $$
0. 1 3 5 \mathrm{V}
$$
G. $$
0. 1 2 5 \mathrm{V}
$$
H. $$
0. 0 4 7 \mathrm{V}
$$
I. $$
0. 0 6 2 5 \mathrm{V}
$$
J. $$
0. 0 5 2 \mathrm{V}
$$
Answer: I
Let \( $n(t)$ \) be a process with a mean of 0 and a two-sided power spectral density of \($\frac{N_{0}}{2}$ = $10^{-6}$W/Hz}\). \( $y(t)$ \) is obtained through an ideal low-pass filter with a cutoff frequency of \( $B = 10$ \) Hz, resulting in \( $y_{0}(t)$ \).
What is the average power of \( $y_{0}(t)$ \)?

Options:
A. $$
0. 0 9 4 \, 8 \, \mathrm{W}
$$
B. $$
0. 0 2 0 \, 7 \, \mathrm{W}
$$
C. $$
0. 0 1 3 \, 5 \, \mathrm{W}
$$
D. $$
0. 0 6 9 \, 2 \, \mathrm{W}
$$
E. $$
0. 0 2 6 \, 3 \, \mathrm{W}
$$
F. $$
0. 0 3 2 \, 0 \, \mathrm{W}
$$
G. $$
0. 0 0 5 \, 9 \, \mathrm{W}
$$
H. $$
0. 0 8 4 \, 3 \, \mathrm{W}
$$
I. $$
0. 0 4 8 \, 1 \, \mathrm{W}
$$
J. $$
0. 0 5 7 \, 6 \, \mathrm{W}
$$
Answer: E
Let \( n(t) = n_{\mathrm{c}}(t) \cos(2\pi f_{\mathrm{c}} t) - n_{\mathrm{s}}(t) \sin(2\pi f_{\mathrm{c}} t) \) be a narrowband stationary Gaussian process. Given that the power of \( n_{c}(t) \) is 1 mW, the power of \( n(t) \) is \(\mathrm{() \quad\mathrm{mW}}\).

Options:
A. 0.5
B. 3
C. 10
D. 0
E. 5
F. 1
G. 4
H. 2
I. 6
J. 8
Answer: F
A DC motor system powered by a single-phase, fully-controlled bridge rectifier circuit requires continuous armature current, with an adjustable average value ranging from $10-100 A$. Given $U_{2} = 220 \mathrm{V}$, considering safety margins, try to find the rated voltage and rated current of the thyristor.

Options:
A. $$
U_{\mathrm{N}}=( \, 7 1 3 \,. \, 4 7 \,-1 0 4 4 \,. \, 2 1 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 7 5. \, 0 8-1 0 2. \, 9 6 \, \right) \mathrm{A}
$$
B. $$
U_{\mathrm{N}}=( \, 5 8 9 \,. \, 9 6 \,-8 9 9 \,. \, 4 2 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 6 5. \, 3 4-9 2. \, 4 6 \, \right) \mathrm{A}
$$
C. $$
U_{\mathrm{N}}=( \, 6 8 3 \,. \, 8 9 \,-9 7 2 \,. \, 4 4 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 7 2. \, 6 7-9 6. \, 2 3 \, \right) \mathrm{A}
$$
D. $$
U_{\mathrm{N}}=( \, 5 4 8 \,. \, 3 1 \,-8 7 2 \,. \, 6 0 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 6 0. \, 4 5-8 6. \, 3 9 \, \right) \mathrm{A}
$$
E. $$
U_{\mathrm{N}}=( \, 7 2 9 \,. \, 5 9 \,-1 0 5 6 \,. \, 7 7 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 7 8. \, 7 1-1 0 0. \, 5 2 \, \right) \mathrm{A}
$$
F. $$
U_{\mathrm{N}}=( \, 6 1 2 \,. \, 3 3 \,-9 2 5 \,. \, 8 3 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 6 8. \, 9 9-9 5. \, 1 0 \, \right) \mathrm{A}
$$
G. $$
U_{\mathrm{N}}=( \, 6 2 2 \,. \, 2 5 \,-9 3 3 \,. \, 3 8 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 6 7. \, 5 6-9 0. \, 0 8 \, \right) \mathrm{A}
$$
H. $$
U_{\mathrm{N}}=( \, 7 0 4 \,. \, 1 0 \,-1 0 3 5 \,. \, 9 6 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 7 4. \, 4 3-9 7. \, 7 2 \, \right) \mathrm{A}
$$
I. $$
U_{\mathrm{N}}=( \, 6 5 7 \,. \, 7 8 \,-9 5 0 \,. \, 1 3 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 7 0. \, 1 2-9 3. \, 8 5 \, \right) \mathrm{A}
$$
J. $$
U_{\mathrm{N}}=( \, 5 9 6 \,. \, 5 4 \,-9 0 3 \,. \, 7 5 \, ) \, \mathrm{V}
$$
$$
I_{\mathrm{N}}=\left( \, 6 3. \, 8 2-9 1. \, 5 9 \, \right) \mathrm{A}
$$
Answer: G
In a single-phase bridge inverter circuit, the DC side voltage $U_{\mathrm{d}}=100 \mathrm{V}$, using bipolar modulation, with a triangular carrier wave amplitude of $10 \mathrm{V}$ and a sinusoidal modulation signal wave amplitude of $8 V$, determine the effective value of the fundamental component of the output voltage.

Options:
A. $72.4V$
B. $54.1V$
C. $56.6V$
D. $52.3V$
E. $60.2V$
F. $68.9V$
G. $45.7V$
H. $63.7V$
I. $58.8V$
J. $49.9V$
Answer: C
A certain resistive load requires a 36V DC voltage, with a maximum load current \(I_{\mathrm{d}} = 30 \mathrm{A}\). Using a single-phase fully controlled bridge rectifier circuit, does supplying power directly from 220V AC and stepping down to 72V using a transformer both meet the requirements? Try to calculate the thyristor conduction angle and the effective value of the load current for both schemes.

Options:
A. $$
6 5^{\circ},28.90(A);
$$;
$$
9 5^{\circ},40.30A
$$
B. $$
4 0^{\circ},48.10(A);
$$;
$$
9 2^{\circ},55.25A
$$
C. $$
4 5^{\circ},22.14(A);
$$;
$$
9 0^{\circ},60.20A
$$
D. $$
5 2^{\circ},68.22(A);
$$;
$$
1 1 0^{\circ},52.17A
$$
E. $$
3 5^{\circ},82.25(A);
$$;
$$
8 8^{\circ},47.10A
$$
F. $$
4 2^{\circ},36.80(A);
$$;
$$
8 7^{\circ},58.20A
$$
G. $$
6 0^{\circ},59.40(A);
$$;
$$
9 3^{\circ},49.10A
$$
H. $$
5 0^{\circ},99.17(A);
$$;
$$
9 6^{\circ},44.15A
$$
I. $$
6 0^{\circ},33.55(A);
$$;
$$
8 5^{\circ},50.30A
$$
J. $$
5 5^{\circ},75.30(A);
$$;
$$
1 0 0^{\circ},39.20A
$$
Answer: H
There is a buck converter circuit operating at a switching frequency of 50kHz, working under continuous inductor current conditions, L= 0.2mH, input voltage $U_{s}=36V$, and output voltage $U_{O}=15V$. If the allowable ripple of the output voltage $\Delta U_{O} / U_{O}=2\%$, find the minimum value of the filter capacitor $c$.

Options:
A. $$
C=8. 0 4 \mu\mathrm{F}
$$
B. $$
C=9. 0 7 \mu\mathrm{F}
$$
C. $$
C=6. 2 2 \mu\mathrm{F}
$$
D. $$
C=5. 4 3 \mu\mathrm{F}
$$
E. $$
C=8. 1 5 \mu\mathrm{F}
$$
F. $$
C=7. 8 6 \mu\mathrm{F}
$$
G. $$
C=6. 9 8 \mu\mathrm{F}
$$
H. $$
C=7. 5 5 \mu\mathrm{F}
$$
I. $$
C=7. 1 0 \mu\mathrm{F}
$$
J. $$
C=7. 2 9 \mu\mathrm{F}
$$
Answer: J
There is a buck chopper circuit with an input voltage $E$ of $27 \ (1 \pm 10\%) \ \mathrm{V}$. The required output voltage $U_{\mathrm{o}}$ is $15 \ \mathrm{V}$. Determine the range of variation for the duty cycle of this circuit.

Options:
A. $$
0. 5 2 \leq\alpha\leq0. 6 3
$$
B. $$
0. 4 9 \leq\alpha\leq0. 5 8
$$
C. $$
0. 5 6 \leq\alpha\leq0. 6 7
$$
D. $$
0. 4 8 \leq\alpha\leq0. 5 9
$$
E. $$
0. 5 0 \leq\alpha\leq0. 6 1
$$
F. $$
0. 5 1 \leq\alpha\leq0. 6 2
$$
G. $$
0. 5 5 \leq\alpha\leq0. 6 5
$$
H. $$
0. 5 7 \leq\alpha\leq0. 6 8
$$
I. $$
0. 5 3 \leq\alpha\leq0. 6 4
$$
J. $$
0. 5 4 \leq\alpha\leq0. 6 5
$$
Answer: F
In a single-phase bridge full-controlled rectifier circuit with inductive load and back electromotive force, if $U_{2}=220 \mathrm{V}$, $E_{\mathrm{M}}=120 \mathrm{V}$ and $R=1 \Omega$, when $\beta=60^\circ$, what's the braking current of the electric motor at this time?

Options:
A. $$
3 8 ( \mathrm{A} )
$$
B. $$
1 5 ( \mathrm{A} )
$$
C. $$
2 1 ( \mathrm{A} )
$$
D. $$
2 7 ( \mathrm{A} )
$$
E. $$
1 2 ( \mathrm{A} )
$$
F. $$
2 5 ( \mathrm{A} )
$$
G. $$
3 0 ( \mathrm{A} )
$$
H. $$
5 0 ( \mathrm{A} )
$$
I. $$
1 8 ( \mathrm{A} )
$$
J. $$
0 9 ( \mathrm{A} )
$$
Answer: C
In a service company parking lot, the number of vehicles arriving during the day is 4 vehicles/h, and the average time each vehicle stays in the parking lot is 0.5 hours. The parking lot has five rows of parking spaces for parking vehicles. In order to evaluate the management performance of the parking lot, try to find the system service index. (Assume that the vehicle arrival rate follows a Poisson distribution and the parking time follows a negative exponential distribution)

Options:
A. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2} {1!}}+{\frac{2^{2}} {2!}}+{\frac{2^{3}} {3!}}+{\frac{2^{4}} {4!}}+{\frac{2^{5}} {5! \times0. 9}}}}=0. 1 7 8 3 4 5
$$
B. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2} {1!}}+{\frac{2^{2}} {2!}}+{\frac{2^{3}} {3!}}+{\frac{2^{4}} {4!}}+{\frac{2^{5}} {5! \times0. 5}}}}=0. 1 6 4 3 2 8
$$
C. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2} {1!}}+{\frac{2^{2}} {2!}}+{\frac{2^{3}} {3!}}+{\frac{2^{4}} {4!}}+{\frac{2^{5}} {5! \times0. 4}}}}=0. 1 8 3 6 2 9
$$
D. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2} {1!}}+{\frac{2^{2}} {2!}}+{\frac{2^{3}} {3!}}+{\frac{2^{4}} {4!}}+{\frac{2^{6}} {5! \times0. 6}}}}=0. 1 3 6 3 2 7
$$
E. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2} {1!}}+{\frac{2^{2}} {2!}}+{\frac{2^{3}} {3!}}+{\frac{2^{4}} {4!}}+{\frac{2^{5}} {5! \times0. 6}}}}=0. 1 3 4 3 2 8
$$
F. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{4} {1!}}+{\frac{4^{2}} {2!}}+{\frac{4^{3}} {3!}}+{\frac{4^{4}} {4!}}+{\frac{4^{5}} {5! \times0. 8}}}}=0. 0 9 8 7 6 5
$$
G. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{2.5} {1!}}+{\frac{2.5^{2}} {2!}}+{\frac{2.5^{3}} {3!}}+{\frac{2.5^{4}} {4!}}+{\frac{2.5^{5}} {5! \times0. 6}}}}=0. 1 2 4 3 5 6
$$
H. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{3} {1!}}+{\frac{3^{2}} {2!}}+{\frac{3^{3}} {3!}}+{\frac{3^{4}} {4!}}+{\frac{3^{5}} {5! \times0. 7}}}}=0. 1 6 5 7 8 9
$$
I. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{1} {1!}}+{\frac{1^{2}} {2!}}+{\frac{1^{3}} {3!}}+{\frac{1^{4}} {4!}}+{\frac{1^{5}} {5! \times0. 5}}}}=0. 2 1 4 3 2 2
$$
J. $$
P ( 0 ) \ ={\frac{1} {1+{\frac{3} {1!}}+{\frac{3^{2}} {2!}}+{\frac{3^{3}} {3!}}+{\frac{3^{4}} {4!}}+{\frac{3^{5}} {5! \times0. 6}}}}=0. 0 7 8 5 4 6
$$
Answer: E
What is the ultraviolet wavelength range with the strongest bactericidal effect?

Options:
A. 300-310nm
B. 250-260nm
C. 320-330nm
D. 350-360nm
E. 260-270nm
F. 265-266nm
G. 280-290nm
H. 240-250nm
I. 290-300nm
J. 270-275nm
Answer: F
The severity of a ligament injury progresses from().

Options:
A. pull to crush
B. strain to split
C. sprain to tear
D. bend to fracture
E. bruise to break
F. twist to snap
G. stress to puncture
H. flex to shatter
I. stretch to rupture
J. twist to cramp
Answer: C
At a certain temperature, the reaction
$$
2 \mathrm{NO} (\mathrm{~g}) + \mathrm{O}_{2} (\mathrm{~g}) = 2 \mathrm{NO}_{2} (\mathrm{~g})
$$
has a rate constant $k = 8.8 \times 10^{-2} \ \mathrm{dm}^{6} \cdot \mathrm{mol}^{-2} \cdot \mathrm{s}^{-1}$. It is known that this reaction is first-order with respect to $\mathrm{O}_{2}$. What is the reaction rate when the concentration of both reactants is $0.050 \ \mathrm{mol} \cdot \mathrm{dm}^{-3}$?

Options:
A. $$
1. 1 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
B. $$
9. 2 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
C. $$
7. 9 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
D. $$
6. 7 \times1 0^{-6} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
E. $$
2. 2 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
F. $$
9. 4 \times1 0^{-6} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
G. $$
3. 1 \times1 0^{-6} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
H. $$
4. 5 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
I. $$
3. 8 \times1 0^{-6} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
J. $$
5. 0 \times1 0^{-5} \mathrm{~ m o l} \cdot\mathrm{d m}^{-3} \cdot\mathrm{s}^{-1}
$$
Answer: A
The X-ray diffraction experiment measured the edge length of the face-centered cubic unit cell of metallic silver to be $408.6 \mathrm{~pm}$. The mass of silver per cubic centimeter is 10.5 g. Given that the relative atomic mass of $\mathrm{Ag}$ is 107.87, what is Avogadro's constant?

Options:
A. $6.18\times 10^{23}\ \text{mol}^{-1}$
B. $6.25\times 10^{23}\ \text{mol}^{-1}$
C. $6.47\times 10^{23}\ \text{mol}^{-1}$
D. $6.12\times 10^{23}\ \text{mol}^{-1}$
E. $6.03\times 10^{23}\ \text{mol}^{-1}$
F. $6.56\times 10^{23}\ \text{mol}^{-1}$
G. $6.10\times 10^{23}\ \text{mol}^{-1}$
H. $5.98\times 10^{23}\ \text{mol}^{-1}$
I. $6.00\times 10^{23}\ \text{mol}^{-1}$
J. $5.92\times 10^{23}\ \text{mol}^{-1}$
Answer: E
In a cylinder with a piston, there is a mixture of air and gasoline vapor, and the initial volume of the cylinder is $40.0 \ \mathrm{cm}^{3}$. If this mixture combusts and releases 950.0 J of heat, at a constant pressure of 86.4 kPa, the gas expands, and all the heat released from the combustion is converted into work to push the piston. What is the volume of the gas after expansion?

Options:
A. $$
9 . 5 \ \mathrm{L}
$$
B. $$
1 4 . 5 \ \mathrm{L}
$$
C. $$
1 0 . 0 \ \mathrm{L}
$$
D. $$
1 1. 0 \ \mathrm{L}
$$
E. $$
8 . 4 \ \mathrm{L}
$$
F. $$
1 2 . 3 \ \mathrm{L}
$$
G. $$
5 . 9 \ \mathrm{L}
$$
H. $$
1 3 . 8 \ \mathrm{L}
$$
I. $$
6 . 1 \ \mathrm{L}
$$
J. $$
7 . 2 \ \mathrm{L}
$$
Answer: D
Given $\mathrm{Fe}^{3+}+\mathrm{e}^{-}=\mathrm{Fe}^{2+}$, $E^{\ominus}=0.77 \mathrm{~V}$, $\left[\mathrm{Fe}\left(\mathrm{CN}\right)_{6}\right]^{3-}+\mathrm{e}^{-}=\left[\mathrm{Fe}\left(\mathrm{CN}\right)_{6}\right]^{4-}$, $E^{\ominus}=0.36 \mathrm{~V}$, $\mathrm{Fe}^{3+}+6 \mathrm{CN}^{-} \rightleftharpoons [\mathrm{Fe}(\mathrm{CN})_{6}]^{3-}$, $K_{Steady state}^{\ominus}=1.0 \times 10^{42}$. What is the $K_{\mathrm{Steady state}}^{\ominus}$ for the reaction $\mathrm{Fe}^{2+}+6 \mathrm{CN}^{-} \rightleftharpoons [\mathrm{Fe}(\mathrm{CN})_{6}]^{4-}$?

Options:
A. $$
7. 4 \times1 0^{3 2}
$$
B. $$
3. 3 \times1 0^{3 1}
$$
C. $$
1. 1 \times1 0^{3 5}
$$
D. $$
4. 7 \times1 0^{3 4}
$$
E. $$
6. 2 \times1 0^{3 6}
$$
F. $$
8. 9 \times1 0^{3 8}
$$
G. $$
5. 6 \times1 0^{3 7}
$$
H. $$
2. 5 \times1 0^{3 3}
$$
I. $$
1. 0 \times1 0^{3 4}
$$
J. $$
9. 8 \times1 0^{3 5}
$$
Answer: C
Given the dissociation equilibrium constant of hydrofluoric acid $K_{\mathrm{a}}^{\ominus} = 6.3 \times 10^{-4}$, and the solubility product constant of lithium fluoride (LiF) $K_{\mathrm{sp}}^{\Theta} = 1.8 \times 10^{-3}$. What is the pH of the solution when LiF achieves precipitation-dissolution equilibrium in 0.5 mol·dm$^3$ hydrofluoric acid?

Options:
A. $4.0$
B. $0.5$
C. $1.8$
D. $5.4$
E. $0.9$
F. $6.7$
G. $2.2$
H. $7.3$
I. $3.1$
J. $8.2$
Answer: G
It is known that a certain bomb calorimeter and its contents have a total heat capacity of 4.633 kJ·K$^{-1}$. When 0.103 g of toluene $\mathrm{C_{7}H_{8}}$ is completely combusted in it, the temperature of the calorimeter rises by 0.944 K. What is the standard molar reaction enthalpy $\Delta_{r}U_{m}$ for the constant volume reaction?

Options:
A. $$-4 2 0 5. 5 \mathrm{~ k J \cdot m o l}^{-1}
$$
B. $$-3 6 0 5. 3 \mathrm{~ k J \cdot m o l}^{-1}
$$
C. $$-3 7 5 9. 8 \mathrm{~ k J \cdot m o l}^{-1}
$$
D. $$-2 9 5 1. 7 \mathrm{~ k J \cdot m o l}^{-1}
$$
E. $$-4 1 2 0. 6 \mathrm{~ k J \cdot m o l}^{-1}
$$
F. $$-3 8 2 7. 1 \mathrm{~ k J \cdot m o l}^{-1}
$$
G. $$-3 4 9 8. 7 \mathrm{~ k J \cdot m o l}^{-1}
$$
H. $$-4 0 1 0. 9 \mathrm{~ k J \cdot m o l}^{-1}
$$
I. $$-2 8 3 0. 2 \mathrm{~ k J \cdot m o l}^{-1}
$$
J. $$-3 9 0 5. 4 \mathrm{~ k J \cdot m o l}^{-1}
$$
Answer: J
Arteriovenous malformation of the brain is a common cerebral vascular anomaly. Which of the following descriptions is correct?

Options:
A. Enhanced CT scan shows varicose veins with mild or unclear mass effect.
B. Enhanced CT scan shows ischemic strokes with detailed lesion outlines.
C. Enhanced CT scan shows necrotic tissue with intense calcification spots.
D. Enhanced CT scan shows brain cysts with vivid contrast enhancement.
E. Enhanced CT scan shows arterial occlusions with minimal artifacts.
F. Enhanced CT scan shows dural sinuses with sharp margins and shadows.
G. Enhanced CT scan shows hemorrhagic areas with defined edges of edema.
H. Enhanced CT scan shows cavernous sinus with significant mass effect.
I. Enhanced CT scan shows embolic blockages with dispersed shadowing.
J. Enhanced CT scan shows aneurysms with complex blood flow patterns.
Answer: A
A Male, 60 years old with headache and localized swelling in the forehead. Physical examination: A ping-pong ball-like mass can be palpated at the site of the forehead swelling. CT shows: Expansion of the frontal sinus with a low-density soft tissue shadow inside, smooth early arcuate edges, and a fine-lined cyst wall can be seen, with an inner CT value of 20 HU. The preliminary diagnosis is ().

Options:
A. Frontal sinus mucocele
B. Epidermoid cyst in frontal scalp
C. Enlarged frontal sinus cyst
D. Enlarged frontal bone osteoma
E. Subgaleal hematoma in frontal area
F. Arachnoid cyst with smooth edges
G. Chronic frontal sinusitis inflammation
H. Infected sebaceous cyst on forehead
I. Hematoma in the frontal region
J. Fibrous dysplasia of frontal bone
Answer: A
The severity of the X-ray findings is disproportionate to the clinical symptoms. This is characteristic of which type of bone metastasis from the following tumors?

Options:
A. Colon cancer bone metastasis
B. Renal cancer bone metastasis
C. Stomach cancer bone metastasis
D. Melanoma bone metastasis
E. Breast cancer bone metastasis
F. Thyroid cancer bone metastasis
G. Prostate cancer bone metastasis
H. Ovarian cancer bone metastasis
I. Pancreatic cancer bone metastasis
J. Lung cancer bone metastasis
Answer: F
Female, 35 years old. A thin-walled cavity in the posterior segment of the upper lobe of the right lung, diameter 3 cm, with a smaller air-fluid level inside. There is exudative lesion around the cavity within the lung, with multiple patchy exudative shadows in the lower lobe of the right lung and the middle and lower zones of the left lung. What is the most likely diagnosis?

Options:
A. Viral Pneumonia (Influenza Infection)
B. Pulmonary Embolism (Embolic Pneumonia)
C. Sarcoidosis (Granulomatous Disease)
D. Fungal Infection (Aspergillus Pneumonia)
E. Pulmonary Tuberculosis (Caseous Pneumonia)
F. Lung Abscess (Suppurative Pneumonia)
G. Chronic Bronchitis (Obstructive Lung Disease)
H. Lung Fibrosis (Interstitial Lung Disease)
I. Bacterial Infection (Staphylococcal Disease)
J. Bronchogenic Carcinoma (Neoplastic Lesion)
Answer: E
Which of the following is the earliest X-ray manifestation of pulmonary congestion?

Options:
A. Duplication in the inferior lobular vein mimics loops.
B. Distension of the anterior lung segment forms webbings.
C. Convergence in the subpleural lymphatics seen as clusters.
D. Constriction in the superior lobebronchi resembles branches.
E. Expansion of the central pleural membrane appears swirling.
F. the upper lobe pulmonary vein resembles a stag's antlers
G. Thickening of the posterior vascular shadow looks wavy.
H. Enlargement in the lateral mediastinal space is cloudy.
I. Constriction along the major airway appears linear.
J. Retraction of the lower pulmonary vein's distal end.
Answer: F
What are the main X-ray findings of mitral valve (left atrioventricular valve) insufficiency in rheumatic heart disease?

Options:
A. Stenosis of the left atrium and pulmonary scarring
B. Dilation of the right atrium and right ventricle
C. Constriction of the right ventricle and atrial septum
D. Narrowing of mitral valve area and aortic dilatation
E. Calcification of the aortic valve and pleural effusion
F. Hypertrophy of the aortic valve and lung consolidation
G. Thickening of the mitral valve and septal shift
H. Dilatation of pulmonary artery and mitral annulus
I. Enlargement of the left atrium and left ventricle
J. Hypertrophy of the right atrium and pericardial effusion
Answer: I
What are MRI imaging and liver mass targets?

Options:
A. T1-weighted image presents a high signal zone with a reduced signal outside the liver parenchyma.
B. T1-weighted image highlights a diminished signal section with equal signal strength in the cardiac tissue.
C. T1-weighted image identifies a faint signal division with a significant signal variance in the intestinal lining.
D. T1-weighted image shows a high signal area with an even higher signal within the pancreatic parenchyma.
E. T1-weighted image captures a stable signal distribution with diversifying signals within the cerebral cortex.
F. T1-weighted image records a signal contrast with an elevated area replicating across the muscle fibers.
G. T1-weighted image reveals a moderate signal area with a lesser signal fluctuation in the renal parenchyma.
H. T1-weighted image displays a uniform signal intensity contrasting within the spleen parenchyma.
I. T1-weighted image indicates a low signal zone with a slightly lower signal within the pancreatic tissue.
J. T1-weighted image suggests an intense signal gradient with balanced signal properties in the lung tissue.
Answer: D
The typical MRI findings for renal cell carcinoma are ().

Options:
A. Visible pseudocapsule signs
B. Regular boundary enhancements
C. Consistent signal intensity
D. Detected fibrotic tissue layers
E. High-intensity cystic regions
F. Distinct tumor calcifications
G. Persistent perinephric fat
H. Notable calcification inclusions
I. Adipose tissue abnormalities
J. Unclear tumor boundary lines
Answer: A
The electric field intensity of a known uniform plane wave is $E=a_{z} E_{z}=a_{z} \ 0.1 \cos (\omega t-k z) \ \mathrm{V/m}$, where $\omega=2 \pi \times 10^{6} \ \mathrm{rad/s}$. Find: the instantaneous energy flux density vector $S$ and the time-averaged energy flux density vector $S_{\mathrm{nv}}$ when $t=0$ and $z=\lambda/8$.

Options:
A. $$
\approx6. 3 5 \times1 0^{-6} a_{x} \quad\mathbf{W} / \mathbf{m}^{2}
$$
B. $$
\approx1. 3 3 \times1 0^{-5} a_{z} \quad\mathbf{W} / \mathbf{m}^{2}
$$
C. $$
\approx5. 6 0 \times1 0^{-7} a_{y} \quad\mathbf{W} / \mathbf{m}^{2}
$$
D. $$
\approx2. 2 0 \times1 0^{-4} a_{z} \quad\mathbf{W} / \mathbf{m}^{2}
$$
E. $$
\approx9. 1 1 \times1 0^{-5} a_{y} \quad\mathbf{W} / \mathbf{m}^{2}
$$
F. $$
\approx4. 1 7 \times1 0^{-4} a_{y} \quad\mathbf{W} / \mathbf{m}^{2}
$$
G. $$
\approx2. 8 9 \times1 0^{-8} a_{z} \quad\mathbf{W} / \mathbf{m}^{2}
$$
H. $$
\approx2. 4 5 \times1 0^{-6} a_{x} \quad\mathbf{W} / \mathbf{m}^{2}
$$
I. $$
\approx3. 8 9 \times1 0^{-3} a_{z} \quad\mathbf{W} / \mathbf{m}^{2}
$$
J. $$
\approx7. 2 4 \times1 0^{-5} a_{x} \quad\mathbf{W} / \mathbf{m}^{2}
$$
Answer: B
A rectangular waveguide filled with air has dimensions of $a \times b = 5 \; \mathrm{cm} \times 2.5 \; \mathrm{cm}$, and supports single-mode transmission. The measured wavelength in the waveguide is 0.25 m. Determine the operating frequency.

Options:
A. $$
3. 4 8 {\mathrm{~ G H z}}
$$
B. $$
3. 1 0 {\mathrm{~ G H z}}
$$
C. $$
3. 0 8 {\mathrm{~ G H z}}
$$
D. $$
2. 9 6 {\mathrm{~ G H z}}
$$
E. $$
3. 3 2 {\mathrm{~ G H z}}
$$
F. $$
2. 7 5 {\mathrm{~ G H z}}
$$
G. $$
3. 2 4 {\mathrm{~ G H z}}
$$
H. $$
2. 8 0 {\mathrm{~ G H z}}
$$
I. $$
3. 6 4 {\mathrm{~ G H z}}
$$
J. $$
3. 5 0 {\mathrm{~ G H z}}
$$
Answer: G
Given that the amplitude of the electric field intensity is $E_{1}=1 \mathrm{~mV/m}$ at a distance of 10 km in the far field in the direction of maximum radiation, find the amplitude value of the magnetic field intensity $H_{3}$ at a distance of 20 km in the direction deviating 60° from the maximum radiation direction.

Options:
A. $$
H3=0.61\mu\mathrm{A} / \mathrm{m}
$$
B. $$
H3=0.58\mu\mathrm{A} / \mathrm{m}
$$
C. $$
H3=0.64\mu\mathrm{A} / \mathrm{m}
$$
D. $$
H3=0.66\mu\mathrm{A} / \mathrm{m}
$$
E. $$
H3=0.63\mu\mathrm{A} / \mathrm{m}
$$
F. $$
H3=0.56\mu\mathrm{A} / \mathrm{m}
$$
G. $$
H3=0.57\mu\mathrm{A} / \mathrm{m}
$$
H. $$
H3=0.59\mu\mathrm{A} / \mathrm{m}
$$
I. $$
H3=0.60\mu\mathrm{A} / \mathrm{m}
$$
J. $$
H3=0.62\mu\mathrm{A} / \mathrm{m}
$$
Answer: D
For a coaxial cable of length 280 m operating at $f = 1.0 \ \mathrm{MHz}$, the measured input impedance at the terminal when short-circuited and open-circuited is $Z_{\mathrm{ins}} = 34.2 e^{-34.4^{\circ}} \ \Omega$ and $Z_{\mathrm{ino}} = 74.8 e^{i 29.2^{\circ}} \ \Omega$, respectively. Given that the phase velocity of the guided wave is $v_{\mathrm{p}} = 2.0 \times 10^{8} \ \mathrm{m/s}$, find the characteristic impedance $Z_{c}$, total attenuation, and phase shift of the coaxial cable.

Options:
A. $$
Z_{\mathrm{c}}=
O+\mathrm{j} P
$$
$$
\begin{array} {l} {{{a l=\frac{3} {2} \mathrm{l n} ( 1, 2 1 3 ) \approx0. 4 7 1 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-3 0. 5^{\circ}+1 5 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
B. $$
Z_{\mathrm{c}}=
A+\mathrm{j} B
$$
$$
\begin{array} {l} {{{a l=\frac{1} {2} \mathrm{l n} ( 2, 9 1 3 ) \approx0. 5 3 5 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 6. 4^{\circ}+1 8 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
C. $$
Z_{\mathrm{c}}=
C+\mathrm{j} D
$$
$$
\begin{array} {l} {{{a l=\frac{3} {4} \mathrm{l n} ( 3, 5 0 7 ) \approx0. 7 2 0 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 8. 7^{\circ}+1 6 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
D. $$
Z_{\mathrm{c}}=
E+\mathrm{j} F
$$
$$
\begin{array} {l} {{{a l=\frac{2} {3} \mathrm{l n} ( 2, 7 8 5 ) \approx0. 6 7 0 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 5. 5^{\circ}+1 9 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
E. $$
Z_{\mathrm{c}}=
Q+\mathrm{j} R
$$
$$
\begin{array} {l} {{{a l=\frac{7} {5} \mathrm{l n} ( 3, 7 2 8 ) \approx0. 7 5 2 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 2. 8^{\circ}+1 1 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
F. $$
Z_{\mathrm{c}}=
I+\mathrm{j} J
$$
$$
\begin{array} {l} {{{a l=\frac{1} {6} \mathrm{l n} ( 2, 9 1 3 ) \approx0. 2 3 8 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 9. 8^{\circ}+1 8 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
G. $$
Z_{\mathrm{c}}=
S+\mathrm{j} T
$$
$$
\begin{array} {l} {{{a l=\frac{5} {9} \mathrm{l n} ( 4, 1 3 9 ) \approx0. 5 1 0 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 3. 1^{\circ}+1 3 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
H. $$
Z_{\mathrm{c}}=
M+\mathrm{j} N
$$
$$
\begin{array} {l} {{{a l=\frac{1} {4} \mathrm{l n} ( 4, 9 3 1 ) \approx0. 3 8 7 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 1. 6^{\circ}+1 2 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
I. $$
Z_{\mathrm{c}}=
G+\mathrm{j} H
$$
$$
\begin{array} {l} {{{a l=\frac{1} {2} \mathrm{l n} ( 6, 9 20 ) \approx0. 5 3 5 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 4. 3^{\circ}+1 7 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
J. $$
Z_{\mathrm{c}}=
K+\mathrm{j} L
$$
$$
\begin{array} {l} {{{a l=\frac{5} {2} \mathrm{l n} ( 3, 9 1 3 ) \approx0. 6 1 4 \quad\mathrm{N}_{p}}}} \\ {{{\beta l=-2 7. 7^{\circ}+1 4 0^{\circ} m \quad( m=0, \pm1, \ \pm2, \ \cdots)}}} \\ \end{array}
$$
Answer: B
The dimensions of a rectangular resonant cavity made of air-filled copper are $a \times b \times l = 22.86$ mm $\times$ 10.16 mm $\times$ 22.5 mm. It is known that this cavity oscillates in the $TE_{101}$ mode, with a maximum electric field amplitude of 500 V/m. What are the average electromagnetic energy storage and the power loss of the cavity?

Options:
A. $$
5. 6 9 \times1 0^{-1 1} \ \mathrm{J} \qquad\qquad,
$$
$$
2. 1 6 \times1 0^{-7} \mathbf{W}
$$
B. $$
7. 6 8 \times1 0^{-1 3} \ \mathrm{J} \qquad\qquad,
$$
$$
2. 0 1 \times1 0^{-9} \mathbf{W}
$$
C. $$
6. 1 0 \times1 0^{-1 2} \ \mathrm{J} \qquad\qquad,
$$
$$
1. 7 3 \times1 0^{-8} \mathbf{W}
$$
D. $$
4. 8 5 \times1 0^{-1 1} \ \mathrm{J} \qquad\qquad,
$$
$$
2. 3 4 \times1 0^{-7} \mathbf{W}
$$
E. $$
6. 3 0 \times1 0^{-1 2} \ \mathrm{J} \qquad\qquad,
$$
$$
1. 9 9 \times1 0^{-8} \mathbf{W}
$$
F. $$
5. 2 0 \times1 0^{-1 1} \ \mathrm{J} \qquad\qquad,
$$
$$
2. 5 8 \times1 0^{-7} \mathbf{W}
$$
G. $$
7. 2 4 \times1 0^{-1 3} \ \mathrm{J} \qquad\qquad,
$$
$$
3. 0 5 \times1 0^{-9} \mathbf{W}
$$
H. $$
4. 5 5 \times1 0^{-1 2} \ \mathrm{J} \qquad\qquad,
$$
$$
1. 8 8 \times1 0^{-8} \mathbf{W}
$$
I. $$
6. 7 5 \times1 0^{-1 2} \ \mathrm{J} \qquad\qquad,
$$
$$
1. 6 1 \times1 0^{-8} \mathbf{W}
$$
J. $$
5. 4 0 \times1 0^{-1 1} \ \mathrm{J} \qquad\qquad,
$$
$$
2. 9 4 \times1 0^{-7} \mathbf{W}
$$
Answer: A
Given a cylindrical resonant cavity with a diameter of $D = 3 \; \mathrm{cm}$, for the same resonant frequency, the cavity length for the oscillation mode $\mathrm{TM}_{012}$ is 1.32 cm longer than that for the mode $\mathrm{TM}_{011}$. Determine the resonant frequency of this resonant cavity.

Options:
A. $$
1 7. 1 \mathrm{~ G H z}
$$
B. $$
1 8. 5 \mathrm{~ G H z}
$$
C. $$
1 4. 2 \mathrm{~ G H z}
$$
D. $$
1 5. 4 \mathrm{~ G H z}
$$
E. $$
1 0. 8 \mathrm{~ G H z}
$$
F. $$
1 2. 9 \mathrm{~ G H z}
$$
G. $$
1 9. 3 \mathrm{~ G H z}
$$
H. $$
1 6. 6 \mathrm{~ G H z}
$$
I. $$
1 3. 7 \mathrm{~ G H z}
$$
J. $$
1 1. 7 \mathrm{~ G H z}
$$
Answer: I
Given a two-port network with a scattering matrix of $\left[ S \right]=\left[ \begin{matrix} {{0.2}} & {{-0.9}} \\ {{-0.9}} & {{0.2}} \\ \end{matrix} \right],$ calculate the absorbed power by the load connected to port ② with a reflection coefficient $\varGamma_{l}=1 / 3$, when the normalized incident wave at port ① is $\dot{u}_{1}^{+}=1$.

Options:
A. 0.413
B. 0.432
C. 0.428
D. 0.419
E. 0.389
F. 0.397
G. 0.473
H. 0.441
I. 0.402
J. 0.451
Answer: A