Xueba, I beg you to go and escort him quickly!

The headmaster brought tea and water from time to time, wiping the cold sweat off his face.

Xu Heng also teased, "Principal, what's wrong with you? You haven't been feeling well lately?"

Pfft!

Who is in poor health!

I'm so scared, okay?

You and these two big shots had such a lively chat!

One of them is the Dean of the School of Physics, Peking University!

One is the head of the Department of Physics of Tsinghua University!

Xu Heng, do you regard them as deans or directors?

He was even joking!

He is still talking and laughing like a good friend of more than ten years!

The principal's eyes widened!

At last.

Director Tan of Tsinghua University probably understood Xu Heng's meaning, got up and left first.

"Student Xu Heng, in this case, let's leave a contact information for each other and keep in touch!"

Xu Heng smiled, "Okay, Director Tan, goodbye."

Having been in contact with so many heavyweights, Xu Heng naturally did not panic.

After exchanging contact information, Xu Heng's eyes fell on Dean Nie, "Dean Nie, you are here this time to take me to visit the Institute of Physics, right?"

Dean Nie smiled, "It's true to cultivate your interest!"

"Before I left in the morning, I arranged for someone to deliver the application form for the visit! I just received the approval result and agreed to let us go."

"So, student Xu Heng, as long as you want, we can leave at any time."

Xu Heng got up, "Then... Dean Nie, please wait for me for a while, I have something to explain to the class."

Xu Heng left the small meeting room.

Dean Nie was confused. He looked at the principal and asked, "I have something to explain. Shouldn't I call my parents? Does he have relatives in his class?"

The principal frowned reluctantly and asked, "Does a girlfriend count?"

Dean Nie, "Eh..."

That's right!

Xu Heng wanted to tell Yue Pingting face to face.

"I'm going out for a few days, and I'll be back in a few days."

Yue Pingting was no longer surprised, "I know."

All she cares about is, "Is your cell phone out of signal or something?"

Xu Heng scratched Yue Pingting's nose, "No, don't worry!"

After explaining, Xu Heng went to the dormitory to pack his things, and then got into the car with Dean Nie.

The car galloped slowly and got on the high speed.

The dean of Peking University's School of Physics drove the car himself, while Xu Heng sat in the back seat.

Dean Nie didn't mind, on the contrary, he was very happy in his heart.

"Student Xu Heng, don't you want to say hello to your family?"

Xu Heng, "No, even if I say it, they are used to it."

Dean Nie, "Eh..."

In the car, he didn't talk about physics with Xu Heng, but mentioned mathematics and literature.

Xu Heng, "Dean Nie, you are quite interesting."

Dean Nie, "?"

Xu Heng, "Are you testing my interest in mathematics and literature?"

Xu Heng's directness stunned Dean Nie for a moment.

He always felt that he was no longer talking to a high school student.

Because Xu Heng not only didn't twitch at all, he even didn't shy away from it, and got straight to the point.

But Dean Nie looked back and thought about it. Xu Heng has even been in contact with such heavyweights as Wu Liubai and Qian Yuejiang, and he himself is no better than Wu Liubai and Qian Yuejiang.

"Hehehe..."

Dean Nie smiled, "So, student Xu Heng, what is your attitude towards these subjects?"

Xu Heng smiled mysteriously, "I can't answer this for you."

Remain mysterious!

Let Dean Nie scratch his heart.

Dean Nie was taken aback again.

Hey!

What a funny kid.

Since the days of mathematics and literature have been chattered to death.

Let’s talk about physics then!

Dean Nie, "Student Xu Heng, you made three professors from our School of Physics sleepless last night, do you know that?"

Xu Heng, "???"

Dean Nie, "Before I came today, they asked me to bring you a gift, in case you would be bored in the car."

With that said, Dean Nie handed Xu Heng a piece of paper.

On paper, it is a physics problem.

It is a new type of question different from the previous ones.

Xu Heng took it over to have a look.

topic:

As shown, two concentric rings of thin metal wires of unequal radii are fixed to a horizontal table top.

The radius of the great circle is R1.The surface insulation radius of the small ring is R2 (R2<<R1), the resistance per unit length of the two ring wires is ro, they are in a uniform magnetic field, the magnetic induction intensity is B, and the direction is vertically downward.

A long straight metal thin rod with a resistance of r1 per unit length is placed on the plane of the large ring, and from the position ab which is R1/100 (>R2) to the left of the center of the ring, it moves right along the horizontal plane at a constant speed of v Slide to a position cd that is symmetrical to ab relative to the center of the large ring, and the metal rod is always in close contact with the large ring during the sliding process.

Assume that the magnetic field generated by the current of the metal rod and the large ring at the small ring can be regarded as a uniform magnetic field.

Find the amount of charge passing through the cross-section of the small ring wire during the sliding process of Shangshu.

Tip: When a section of arc wire with radius R and length l flows with current I, the magnetic induction intensity generated by the arc current at the center of the circle is B=kmlI/R2, and the direction is perpendicular to the arc and shrinks in the plane and is in line with the circle The direction of the arc current satisfies the right-hand spiral rule; when the infinitely long straight wire passes through the current I, the magnitude of the magnetic induction intensity B generated by the current at a distance r from the straight wire is B=km2I/r, where km is a known constant.

After reading the topic.

Xu Heng smiled slightly.

Everyone has a problem!

It's just that sometimes, no matter how many times you hear others say it, even if you believe it yourself.But when I really have the opportunity, I still want to try again.

I want to test whether the person in front of me is like what other people said!

Dean Nie, this should be the mentality now.

Simultaneously.

Xu Heng also realized that with the different types of questions, everyone gave up trying to test his own background, and started to test how many aspects of physics he knew!

That is to say, which category is good at!

Is it a magnetic field, or mechanics, or something else...

These guys really persevere!

Xu Heng frowned slightly.

Dean Nie looked at Xu Heng's strange expression through the rearview mirror, and thought: Could it be that Xu Heng is not very good at this type of questions?

Or……

Suddenly Dean Nie realized that he had not given Xu Heng a pen and paper.

"Sorry, there is a pen and paper in front of you, just take it yourself!"

Xu Heng, "No, I won't use it."

……

PS: Thanks to [Wuxin] [Yuetang] [Text] [The Only One in My Life] [A Kang] [I Love to Smile in the Red Dust] for their support!

thanks for your support!Must get rich!Peach Blossom MAX!

Kneel for all support!There are more updates below! .

Chapter 174

No...no need?

How do you solve this problem without a pen?

Dean Nie lost his mind for a while, and all kinds of legends about Xu Heng began to come to mind.

it is true?

impossible……!

For some simple questions, he can do the calculations with his mouth and brain, but this question is so difficult, how is it possible? !

So, what does Xu Heng mean?

Dean Nie observed Xu Heng through the rearview mirror from time to time.

The atmosphere in the car gradually became strange.

Dean Nie drove the car at a speed between 110 and 120.

It was on and on, and Dean Nie saw that Xu Heng was still silent, so he really wanted to ask directly, but he still didn't ask when he opened his mouth several times.

What if Xu Heng was thinking?

Didn't his sudden question interrupt Xu Heng's train of thought?

In addition, if Xu Heng doesn't know this question and is depressed, wouldn't it be even more inappropriate to ask it by himself.

With this thought in mind, Dean Nie gradually had his own answer in mind.

It seems that Xu Heng is not as powerful as the rumors say, but he is still just a high school student!

Fortunately, he still has a lot of room for improvement!

I was thinking about these.

Xu Heng said suddenly, "You can make dotted lines on the map..."

"When the long straight metal rod slides horizontally to the right at the position ab with the speed v..., due to the cutting of the magnetic field line, the magnitude of the induced electromotive force from b to a in the metal rod is ε=BLv..."

"..."

“位置时与大圆环两接触点间的长度，由几何关系有L=2根号下（R12-（R1/100）2），约等于2R1……”

"During the slide of the metal rod from position to cd, the metal rod and..."

"..."

"In the process of the metal rod sliding from ab to cd, the metal rod is near the center of the circle, so the metal rod can be approximately regarded as an infinitely long straight wire. It is suggested that when the metal rod is at the ab position, the magnetic induction intensity generated by the current in the rod The size is..."