My IQ has been increasing year by year.

The exam paper was opened, and there were three major questions in total.

The first question is about thermodynamics; the second question is about optics; and the third question is about weak electrical signal acquisition and amplification.

Three separate experiments, sharing the three-hour exam time.

The blue tray did not contain any neatly categorized and packaged equipment boxes.

Optical bare lens, thermal single-layer aluminum cup, electrical bulk resistor, breadboard, eight-pin chip without model number, and several wires of varying lengths.

Everything was mixed together haphazardly, like a cheap hodgepodge.

To complete these three experiments, candidates must sort out the necessary parts from the pile of scrap metal and plan the construction sequence for the three hours themselves.

The top students, accustomed to high-precision instruments, froze briefly as they held their pens and looked at the tray.

Chen Zhuo picked up the test paper and glanced at the assessment objectives and required parameters for the three major questions.

Two minutes later.

He started to take action.

The thermal aluminum cup was pushed to the upper left corner.

The optical lens and semiconductor laser pointer were carefully placed on the draft paper in the upper right corner.

The remaining electrical components were left in the center of the tray.

He chose to tackle the toughest challenge first: the eight-pin chip with its silkscreen markings ground off and no model number markings.

The boy to my left was flipping through his test paper in frustration, trying to find clues about pin definitions from the lengthy questions.

This is a gamble. If the connection is reversed, the chip will burn out the moment it is powered on, and you will get zero points on the third question.

Chen Zhuo picked up the digital multimeter from the corner of the table.

Press the power button and turn the black knob in the middle to the diode test setting.

He held the black chip in his left hand.

Hold the red and black markers in your right hand.

Inside any physical entity, as long as it is a transistor or a PN junction, it follows the most basic principles of unidirectional conductivity and voltage drop.

There are no instruction manuals; the laws of physics are the instruction manual.

The black probe is fixed to one pin on the edge, and the red probe is quickly passed over the other seven pins in sequence.

The numbers on the multimeter's LCD screen start to fluctuate. This could indicate an open circuit signal or the forward voltage drop of a diode.

Change the reference pin and repeat the previous steps.

The movements are mechanical and regular, without any unnecessary pauses.

Less than a minute.

Chen Zhuo put down his pen.

He drew a simple box on the draft paper, marking GND in the lower left corner and VCC in the upper right corner.

The power supply and ground wire have been found.

The soldering iron tip is pressed against the connection between the wire and the external sensor.

The solder wire is placed against it.

A wisp of smoke rose, and the scent of pine resin filled the air.

Remove the soldering iron.

A smooth, full, and burr-free teardrop-shaped solder joint is formed instantly.

The muscle memory honed over the past two weeks in the Jinling Laboratory, surrounded by piles of junk, has now transformed into the most ruthless efficiency. First Teaching Building.

2:40 PM.

A fine layer of sweat appeared on He Gui's forehead.

He is making good progress; the thermal experiments have been completed, and he is now working on the second problem: the acquisition of weak photoelectric signals.

The signal level for this question is in the millivolt range, making it extremely sensitive.

He Gui's experimental table was on the far left of the classroom, right next to the wall.

He looked at the two ordinary insulated wires, each half a meter long, in the tray without any shielding.

My gaze shifted and landed on the white wall right next to the edge of the table.

There is a row of white plastic inspection covers at the bottom corner of the wall.

He Gui stood up.

Grasp the edge of the wide lab table with both hands and apply slight pressure.

With a dull screech, he forcefully slid the heavy lab table slightly to the right, away from the wall. After sitting down, he picked up the two thin wires.

Hold one end with your left hand, hold the other end with your right hand, and twist it firmly in the opposite direction.

The two wires, one red and one black, were twisted together tightly and evenly like a braid.

Twisted pair cable.

The opposing magnetic fields generated by two closely spaced wires are used to cancel out common-mode interference from the outside world.

He connected the twisted wires to the circuit and turned on the small oscilloscope on the table.

On the screen, a clear, clean green waveform swept smoothly.

He subconsciously turned his head and glanced at the out-of-province boy sitting to his right.

That boy was also working on the third question.

His wires were scattered haphazardly on the table, and the lab bench was very close to the wall.

At that moment, the boy was staring intently at the oscilloscope, patting the instrument's casing with his hand.

On the screen, a thick, blurry, jagged band of light was pulsating wildly.

The 50 Hz power frequency interference generated by the main power cable inside the wall has completely drowned out the real weak signal.

The boy was so anxious that he kept fidgeting with his hands, repeatedly checking the wiring, but he couldn't find the source of the interference at all.

Science Building.

It was exactly 3 p.m.

The sun is setting in the west.

The blinding sunlight shone precisely through the tinted glass on the west side onto Zhou Kai's lab table.

A large, bright spot of light formed on the tabletop.

Zhou Kai had just finished the electricity problem and was about to start the third problem, optical interferometry.

The tray contained no graduated metal optical bench, only three bare lenses, a semiconductor laser held in place by an iron stand, and a sheet of white paper serving as a screen.

He needed to trace a straight optical axis on a blank sheet of paper without any guides, relying entirely on his eyesight and hands, and then read the spacing of the interference fringes. The moment the sunlight shone down.

The faint red interference fringes on the white paper instantly disappeared into a bright area.

Zhou Kai put down the lens in his hand.

He raised his right hand.

In the quiet examination room, this action immediately caught the attention of the invigilator.

The proctor walked over quickly.

Zhou Kai pointed to the sunlight on the table, and then to the gap in the ceiling above the window.

"Teacher, the direct sunlight has disrupted the dark field environment, making it impossible to observe the interference fringes. Please pull down the blackout curtain in this area."

The voice was steady, and the reason was valid.

The proctor glanced at the desk and nodded.

He turned and walked to the window, pulling the hidden bead.

The heavy, dark gray blackout curtains slowly descended.

Zhou Kai's experimental table was once again enveloped in a dim light suitable for optics.

On the white paper, those fine red stripes reappeared clearly.

Zhou Kai picked up a ruler, brought it close to the screen, and began recording data.

Four o'clock in the afternoon.

There is one hour left before the exam ends.

Soft footsteps echoed down the corridor.

The elderly expert who spoke at the opening ceremony that morning walked around the examination rooms with his hands behind his back.

He didn't go inside, but observed the candidates' condition through the glass window of the back door.

The old expert's expression was not relaxed.

The experimental equipment used in this experiment was deliberately made to look old and rough by the test-setting team.

The purpose of mixing the components of the three subjects is also to test students' ability to coordinate the overall situation.

The goal is to break these gifted young people's blind faith in ideal models.

He walked past an exam room and saw a girl doing the first question, a thermal experiment.

The calorimeter distributed by the organizing committee was an ordinary single-layer aluminum cup without insulation.

Heat is lost extremely quickly.

The specific heat capacity measured by the girl was nearly 30 percent different from the standard value in the textbook.

She stared at the data on the draft paper, her hand holding the pen stiffening slightly.

Finally, she picked up the eraser.

I erased the actual temperature changes bit by bit, and then painstakingly added back a few numbers with a pen, piecing together a pretty result that was close to the standard value.

The old expert looked out the window and shook his head slightly.

He sighed and continued walking.

Falsifying data to conform to a non-existent standard answer.

My footsteps stopped outside the back window of classroom 402 in the third teaching building.

The old expert's gaze fell on a boy in the third row by the window.

It is Chen Zhuo.

On Chen Zhuo's desk, the circuit built from loose parts was already powered on, and the optical lens had its optical path marked on a piece of white paper. Next to it was the cooled single-layer aluminum cup.

The practical portion of all three experiments has been completed.

He is writing an exam paper.

The old expert had excellent eyesight and could roughly see the layout of Chen Zhuo's paper through the glass.

Chen Zhuo's data record table was filled with numbers.

If calculated according to the standard model, the data measured by Chen Zhuo would also be very poor, with a huge error.

But Chen Zhuo didn't take the eraser.

There were no signs of correction on his paper.

Even the most unflattering data was captured and imprinted on the answer sheet with black ink.

The old expert's gaze shifted downwards.

It landed on the last half of the exam paper, in a large blank area.

Chen Zhuo was writing there.

It's not about finding answers; it's about writing lines of rigorous mathematical formulas.

The experienced expert was able to clearly see the symbols.

Partial derivatives.

Absolute error.

The square root of the relative error.

That's the systematic error propagation formula that you only encounter in university physics experiments.

Chen Zhuo did not attempt to cover up the instrument's defects.

He readily accepted the heat leakage of the single-layer aluminum cup, the inherent resistance of the inferior wires, and the poor contact in the breadboard socket. He transformed all these defects into mathematical language.

The pen tip moved quickly across the paper.

He clearly listed three sources of error on the exam paper.

First, Newtonian cooling convection losses caused by the ambient temperature gradient.

Second, the high-frequency voltage division effect caused by the internal resistance of the non-ideal voltage source.

Third, fluctuations in contact resistance at the connection points of individual components.

Finally, he substituted these error terms into the formula and calculated a huge error range.

And with that, a period was drawn after this imperfect, real data.

The old expert stood outside the window and quietly watched Chen Zhuo write the last line.

In this quiet examination room.

There are no shortcuts, and no miraculous inventions to turn the tide.

With the most clumsy yet honest attitude, I delved into the real world of physics, facing a lab table full of flaws.

The old expert did not push the door open and go in.

He simply stood outside the glass window, watching the boy put down his pen.

The wrinkles around her eyes gradually smoothed out.

He didn't speak.

Turning around, I walked down the corridor to the next exam room.

Five o'clock in the afternoon.

A long, drawn-out electric bell rang.

"Exam over. Everyone stand up and remove your hands from the table."

The proctor's voice drowned out the bell.

Chen Zhuo stood up, his hands hanging naturally at his sides.

The examination room was filled with the sounds of equipment being packed up and chairs being pushed back.

Chen Zhuo turned his head and glanced out the window.

The sun had completely set behind the buildings, and the sky was a weary gray-blue.

The personal battlefield has finally come to an end.