My IQ has been increasing year by year.

Four o'clock in the afternoon.

The sky over Nanjing remains bright.

Sunlight streamed obliquely into the small lecture hall through the glass windows of the third-floor corridor of the administration building.

The classroom was quiet.

Only the air conditioner in the corner was blowing out a cool breeze.

It stirred the stuffy air, emitting a monotonous buzzing sound.

On the blackboard.

The diagram of a DC motor and a suspended weight, made up of a few simple chalk lines, remained there quietly.

It is labeled U, R, m.

Professor Wang sat on a wooden chair behind the podium.

He was holding a chipped enamel mug with the words "Labor is the most glorious" printed on it.

He didn't look at the students below, but his gaze fell on a few tea leaves floating in the teacup.

Occasionally, I'd blow a breath and take a sip.

Below the podium.

Six junior high school students were scattered in the first two rows of the lecture hall.

The thirty-minute countdown felt like an invisible hand, slowly tightening the air in the classroom.

Wang, who spoke little, sat in the second row.

His black pen flew across the draft paper, marking names rapidly.

Write down a formula.

pause.

His brows were tightly furrowed, almost forming a knot between them.

Then, forcefully cross out that formula.

The pen tip left a deep black mark on the paper, almost tearing it.

He wanted to use Ohm's law.

The most core and fundamental law of electricity in junior high school physics.

However, Professor Wang's words just now were like a bucket of cold water.

The motor will burn out when it gets stuck, but it won't when it's running.

If we apply Ohm's law directly, the current is a constant, and the heat generated is also a constant.

This fails to explain the significant difference in motor heating between rotating and jammed states.

Wang, who was not talkative, grabbed a handful of his short hair in frustration.

He felt like his mind was a tangled mess, and he couldn't untangle the threads no matter what he did.

Miao Shi'an was sitting to his right.

The collar of the white shirt was already slightly damp with sweat.

The eyes behind the gold-rimmed glasses were fixed on the diagram on the blackboard.

His draft paper contained many equations about energy transformation.

Electrical energy, mechanical energy, and internal energy.

He realized that the energy was going to more than one place.

But he got stuck in a fatal spot.

He didn't know how to express the reverse voltage generated by the internal coil of the electric motor cutting magnetic field lines using an algebraic expression.

The pen tip hovered on the paper, hesitant to fall.

In the corner by the window.

He Gui gripped the pen tightly.

His palms were sweaty, and his grip on the pen was somewhat stiff.

He looked at the calculation process that filled half a page, all of which was based on the derivation of ideal conditions.

He silently turned the page and started again.

Zhou Kai was holding a Parker pen in his hand.

The pen moved across the paper, writing down a series of complex mathematical derivations.

He discovered the limitations of physical formulas and attempted to use his powerful mathematical calculation abilities to forcibly construct a micro-element model to arrive at that velocity v.

His calculation speed is extremely fast.

However, in each iteration of the derivation, the units could never be standardized.

It's either one ampere more or one volt less.

In the classroom, the only sound was the scratching of pens on paper.

There was also the occasional soft sound of turning pages.

Time passed by, second by second.

As the sunlight outside lowered, the light inside the classroom gradually turned yellowish.

Lin Yi sat in the middle of the first row.

She didn't draw any force analysis diagrams on the draft paper at all.

He didn't even pick up a pen.

He leaned back in his chair in complete relaxation, one leg trembling slightly.

She rested her chin on one hand and tapped the table with a very rhythmic motion with the other.

Tap, tap, tap.

The voice was very soft, as if someone was humming an unknown pop song in their mind.

She looked at the extremely simple diagram of an electric motor on the blackboard.

I watched it for about five minutes.

"cut."

Lin Yi muttered something in a very low voice.

"That old man's pretty good at digging holes."

She finally managed to sit up straight and stretched out a big yawn.

Then, he casually picked up the black water-based pen on the table.

The pen tip landed on the white paper.

There were no alterations.

Her handwriting was somewhat flamboyant, but her logic was extremely clear.

She didn't care about the complicated expression of back electromotive force, nor did she get hung up on how the current changed.

Those are all just going in circles.

Conservation of energy.

It's such a simple thing.

The electrical energy supplied by the power source is partly converted into the internal energy of the coil to generate heat, and the rest is used to lift the wooden block to do mechanical work.

Lin Yi wrote down lines of equations on the paper with remarkable fluency.

After writing this core equation.

She didn't pause.

The water-based pen glides across the paper extremely quickly.

What she needs to find is the maximum speed v.

Transforming the equation, we obtain a quadratic equation in one variable concerning the current I.

Formula, find the extreme value.

Less than three minutes.

Three lines of extremely clean algebraic expressions.

Lin Yi drew two horizontal lines under the answer in a very casual manner.

"Done."

She muttered something under her breath, her voice tinged with a sense of ease and smugness.

Then, pick up the pen cap.

With a snap.

The pen cap was attached to the pen barrel.

Less than ten minutes.

Lin pushed the draft paper forward.

He slumped back into his chair, crossed his arms, and began counting the cracks in the ceiling, somewhat bored.

Chen Zhuo was sitting diagonally behind her.

I heard the soft click of the pen cap being snapped shut.

The movements of the hands were not affected in any way.

Chen Zhuo's draft paper was completely different from Lin Yi's blank space.

The paper was covered with dense writing.

He didn't have Lin Yi's ethereal intuition that allowed him to see through the essence of physics at a glance.

His problem-solving method is an extremely solid and rigorous brute-force approach.

With the pen in his hand, he drew a complete equivalent circuit diagram on the paper.

Separate the coil resistor inside the motor.

A virtual power source representing the back electromotive force is connected in series in the circuit.

Next to it, the force balance of a heavy object rising at a constant speed is marked with the most basic mechanics formulas.

He described an extremely complex dynamic process.

Like disassembling a mechanical clock, it was broken down into the most basic and uncontroversial parts.

Then, using a tight logical chain, these parts are reassembled.

Electrical work W=UIt.

Joule heat Q = I^2Rt.

Mechanical work E=mgvt.

Three separate formulas are listed.

Jointly established.

Eliminate time t.

Ink is rubbed onto white paper.

Chen Zhuo drew the last score line.

Write down the final algebraic expression.

His answer and Lin Yi's answer were completely consistent in their final form.

Same way.

Chen Zhuo put down his pen.

The pen tapped lightly on the table, making a soft, woody clinking sound.

Lin put down his pen.

Less than forty seconds had passed.

Two tiny sounds.

Two completed answer sheets.

None of the four boys sitting next to him looked up.

However, their writing movements became noticeably stiff.

The air in the classroom seemed to have become thicker.

An invisible, enormous psychological gap weighed on their hearts, like a stone pressing down on their chests.

They were all number one in their respective cities.

He was a genius in the eyes of his teachers, but a monster in the eyes of his classmates.

But now, on this ordinary afternoon.

In just ten minutes.

That invisible chasm called talent and foundation stood between them.