He opened the exam paper to find three major sections.
Question one: thermodynamics. Question two: optics. Question three: weak electrical signal acquisition and amplification.
Three independent experiments, all to be completed within the shared three-hour exam period.
But in the blue tray, there were no neatly categorized and packaged equipment kits.
Bare lenses for optics, a single-walled aluminum cup for thermodynamics, loose resistors and a breadboard for electronics, an eight-pin chip with no model number, and a few wires of varying lengths.
Everything was jumbled together with no rhyme or reason, like a cheap hodgepodge.
To complete the three experiments, the candidates had to sort through this pile of junk to find the necessary components and plan their own workflow for the three-hour period.
The top students, accustomed to high-precision, cutting-edge instruments, held their pens and stared at the trays, momentarily frozen.
Chen Zhuo picked up the test paper, his eyes scanning the objectives and required parameters for the three sections.
「Two minutes later.」
He got to work.
The aluminum cup for the thermodynamics experiment was pushed to the top-left corner.
The optics lenses and the semiconductor laser pen were placed carefully on a piece of scratch paper in the top-right corner.
The remaining electronics components were left in the center of the tray.
He chose to tackle the toughest nut first: the eight-pin chip, its silk-screened markings ground off, leaving no model number or specifications.
The boy to his front-left was flipping through the paper irritably, trying to find a hint about the pinout in the lengthy problem description.
It was a gamble. If he wired it incorrectly, the chip would burn out the instant power was applied, resulting in a zero for the third question.
Chen Zhuo picked up the digital multimeter from the corner of his desk.
He pressed the power button and turned the black dial in the center to the diode test setting.
He held the black chip in his left hand.
In his right, he held the red and black test probes.
Inside any physical component, as long as there are transistors and P-N junctions, they follow the fundamental principles of unidirectional conductivity and voltage drop.
Without a manual, the laws of physics become the manual.
He held the black probe steady on one of the edge pins while quickly tapping the red probe against the other seven pins in sequence.
The numbers on the multimeter’s LCD screen began to flicker—an open circuit signal, or the forward voltage drop of a diode.
He switched to a new reference pin and repeated the process.
His movements were mechanical and methodical, with no wasted motion or hesitation.
In less than a minute, Chen Zhuo set down the probes.
He drew a simple rectangle on his scratch paper, labeling GND in the bottom-left corner and VCC in the top-right.
He had found the power and ground pins.
He pressed the tip of the soldering iron against the connection point between a wire and an external sensor.
The solder wire touched the joint.
A wisp of blue smoke rose, and the scent of rosin filled the air.
He pulled the iron away.
A smooth, full, teardrop-shaped solder joint, completely free of burrs, had formed in an instant.
The muscle memory he had honed over the past half-month facing down piles of junk in the Jinling Laboratory now translated into cold, hard efficiency.
「First Academic Building.」
「2:40 PM.」
A thin layer of sweat beaded on He Gui’s forehead.
His progress wasn’t slow. He had already finished the thermodynamics experiment and was now working on the second question, weak photoelectric signal acquisition.
The signal for this problem was in the millivolt range and extremely sensitive.
He Gui’s lab bench was on the far left side of the classroom, right up against the wall.
He looked at the two half-meter-long, unshielded, ordinary insulated wires in his tray.
His gaze shifted to the white wall right next to the edge of his desk.
Near the bottom corner of the wall was a row of white plastic access panel covers.
He Gui stood up.
He gripped the edges of the wide lab bench with both hands and pushed.
With a dull scraping sound, he managed to shove the entire heavy lab bench slightly to the right, away from the wall.
After sitting back down, he picked up the two thin wires.
Holding one end in his left hand and the other in his right, he twisted them in opposite directions.
The red and black wires were twisted together tightly and evenly, like a rope.
A twisted pair.
Using the opposing magnetic fields generated by two closely placed wires to cancel out external common-mode interference.
He Gui connected the twisted wires to the circuit and turned on the small oscilloscope on his desk.
On the screen, a clear, clean green waveform swept steadily across.
He subconsciously glanced over at the boy from out of province sitting to his front-right.
That boy was also working on the third question.
His wires were spread messily across his desk, and his lab bench was very close to the wall.
Right now, the boy was staring intently at his oscilloscope, smacking the side of the instrument’s casing.
On his screen, a thick, blurry, static-filled wave band was jumping around wildly.
The 50 Hz power-line hum from the main electrical cables inside the wall had completely drowned out the real, weak signal.
The boy was anxiously picking at his hands and repeatedly checking his wiring, but he couldn’t find the source of the interference.
「Science Building.」
「3:00 PM.」
The sun was starting to set in the west.
Blinding sunlight shone through the tinted west-facing windows, landing precisely on Zhou Kai’s lab bench.
A large, bright patch of light formed on his desk.
Zhou Kai had just finished the electronics problem and was preparing to start the second question: optical interference measurement.
The tray didn’t contain a graduated metal optical bench, only three bare lenses, a semiconductor laser held by an iron stand, and a sheet of white paper to serve as a screen.
He had to align a perfectly straight optical axis on the trackless paper, relying entirely on his eyes and hands, and then measure the spacing of the interference fringes.
The moment the sunlight hit his desk, the already-faint red interference fringes on the white paper vanished in the glare.
Zhou Kai put down the lens he was holding.
He raised his right hand.
In the quiet exam hall, the gesture immediately caught the proctor’s attention.
The proctor walked over quickly.
Zhou Kai pointed at the sunlight on his desk, then at a gap in the suspended ceiling above the window.
"Sir, the direct sunlight is ruining the dark-field environment, making the interference fringes impossible to observe. I request that you lower the blackout curtain for this area."
His voice was steady, his reasoning sound.
The proctor glanced at the desk and nodded.
He turned, walked to the window, and pulled a hidden beaded chain.
A heavy, dark gray blackout curtain slowly descended.
Zhou Kai’s lab bench was once again plunged into the dimness suitable for an optics experiment.
On the white paper, the fine red fringes reappeared clearly.
Zhou Kai picked up a ruler, leaned close to the paper screen, and began to record his data.
「4:00 PM.」
There was one hour left until the end of the exam.
The faint sound of footsteps came from the hallway.
The old expert who had spoken at the opening ceremony that morning was strolling outside the exam rooms, his hands clasped behind his back.
He didn’t go inside, merely observing the students’ conditions through the glass windows on the back doors.
The old expert’s expression was not relaxed.
The equipment for this exam had been deliberately made to look old and crude by the question-setting committee.
Jumbling the components for the three subjects together was also intended to test the students’ ability to manage the overall situation.
The goal was to shatter these young geniuses’ blind faith in ideal models.
He passed one exam room and saw a girl working on the first question, the thermodynamics experiment.
The calorimeter provided by the committee was just an ordinary, single-walled aluminum cup with no insulation layer.
Heat dissipated extremely quickly.
The specific heat capacity the girl measured was off from the standard textbook value by nearly thirty percent.
She stared at the data on her scratch paper, her pen-holding hand somewhat stiff.
Finally, she picked up her eraser.
She erased the actual temperature changes she had recorded, bit by bit, and then forced the numbers, fudging them to produce a "pretty" result that was close to the standard value.
Watching from outside the window, the old expert shook his head slightly.
He sighed and continued on his way.
’Falsifying data to conform to a nonexistent standard answer.’
His footsteps halted outside the back window of Classroom 402 in the Third Academic Building.
The old expert’s gaze fell on a boy in the third row by the window.
It was Chen Zhuo.
On Chen Zhuo’s desk, the circuit he’d built from loose components was powered on, the optical path for the lenses was marked out on the white paper, and next to it all sat the now-cooled, single-walled aluminum cup.
The practical portions of all three experiments were complete.
He was now writing on the exam paper.
The old expert had excellent eyesight. Through the glass, he could roughly make out the layout of Chen Zhuo’s answer sheet.
Chen Zhuo’s data tables were filled with numbers.
If calculated according to the standard model, the sets of data Chen Zhuo had measured would also look terrible, with huge errors.
But Chen Zhuo hadn’t reached for his eraser.
There were no signs of alteration on his paper.
The real data, no matter how ugly, was fixed onto the answer sheet in black ink.
The old expert’s eyes moved downward.
They fell upon the large, blank half-page at the end of the exam paper.
Chen Zhuo was writing there.
He wasn’t fudging answers, but writing line after line of rigorous mathematical formulas.
The old expert could make out the symbols.
Partial derivatives.
Absolute error.
Root mean square of relative error.
Those were the formulas for the propagation of systematic error, something one would only encounter systematically in a university-level physics lab.
Chen Zhuo wasn’t trying to hide the equipment’s flaws.
He had calmly accepted the heat loss from the single-walled cup, the inherent resistance of the poor-quality wires, and the bad connections in the breadboard’s sockets.
He converted all of these flaws into the language of mathematics.
The tip of his pen flew across the paper.
He clearly listed three sources of error on his paper.
First, convective loss due to Newton’s law of cooling, caused by the ambient temperature gradient.
Second, the high-frequency voltage division effect caused by the internal resistance of a non-ideal voltage source.
Third, fluctuations in contact resistance at the component connection points.
Finally, he plugged these error terms into the formulas and calculated a massive margin of error.
And after this imperfect yet real data, he drew a period.
The old expert stood outside the window, silently watching as Chen Zhuo wrote the last line.
In this quiet exam hall, there were no shortcuts, no miraculous, tide-turning inventions.
Only the most honest, if seemingly clumsy, approach—facing a lab bench full of flaws and diving headfirst into the world of real physics.
The old expert did not push open the door and enter.
He simply stood outside the glass window, watching the young man set down his pen.
The wrinkles at the corners of his eyes slowly smoothed out.
He said nothing.
He turned and walked down the hall toward the next exam room.
「5:00 PM.」
A long electric bell rang.
"The exam is over. All students, please stand up and take your hands off your desks."
The proctor’s voice boomed over the bell.
Chen Zhuo stood up, his hands hanging naturally at his sides.
The sounds of equipment being packed away and chairs scraping against the floor filled the exam hall.
Chen Zhuo turned his head and glanced out the window.
The sun had completely set behind the buildings, and the sky had faded to a weary, grayish blue.
His personal battlefield had finally fallen silent.

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