At this moment, Li Zheng stared blankly ahead.

He didn't feel like he had learned anything.

But he was confident that he understood everything.

No matter what question was thrown at him, he had the answer.

Feeling a mysterious confidence.

Li Zheng's entire scalp became numb.

It’s a new realm!

There is no trick to win without a trick!

At this moment, Xu Zhu is not alone.

Feng Qingyang, Zhang Sanfeng, and Dugu Qiubai, their souls merged at this moment!

"I...I understand..." Li Zheng looked at Xie Qifan and burst into tears of gratitude, "Thank you, Teacher Xie, thank you!!"

"..." Jie Qifen held the draft paper and took a step back in shock, "I...I didn't do anything. You can just call me Lao Jie. Crab is my nickname, and only my mother can call me that."

"thanks, thanks!"

"..." Jie Qifan looked at Li Zheng worriedly, then picked up two pieces of draft paper and looked at it for a while, and couldn't help but sigh, "It's not easy to come up with so many... But I can see that you are average in mathematics and method.

You're still very stupid. To be honest, we still don't get along... I'm not sure I can continue to teach you."

"It doesn't matter, this lesson is already very good." Li Zheng nodded repeatedly.

"Your attitude is quite comfortable..." Jie Qifen put down the draft paper and raised his hand and said, "Okay, as I said before, I will give you a final question. If you can solve it, I will continue to talk."

"please!"

"Let's take a simple fluid mechanics question. I'll say it once, listen up -" Jie Qifen raised the corner of his mouth and gave a wicked smile, "How much electricity can a drop of water carry at most?"

Li Zheng waited blankly for a long time, everyone just laughed and said nothing, and then he suddenly realized.

"that's all?"

"That's it." Jie Qifen gestured, "You can set the conditions as you like, whether it's a cube water droplet or a sphere, it can have gravity or no gravity, that's it."

"Ah." Li Zheng opened his mouth, "Okay..."

"You can do whatever you want, just forget it." Jie Qifen rubbed Li Zheng's head, then put his pocket in his pocket and left the classroom.

When he turned around to close the door, he bumped into Lu Yang.

"Teacher Xie, the work in the laboratory is almost finished. Can you let everyone go to dinner?"

"Well, let's take them there." Jie Qifen leaned against the door of the classroom and waved casually.

"You're not going?"

"I'll wait a little longer."

"Oh..." Lu Yang glanced from the door and window. It took a lot of effort to find Li Zheng in the back row of the classroom, and then he said in surprise, "Li Zheng is back?"

"Um."

"Why don't you go to the lab?"

"Isn't this dissatisfaction?" Jie Qifen smoked a cigarette and said with a smile, "Look for me by name."

"Ah!" Lu Yang trembled and looked into the classroom again.

Full of regret and compassion.

What are you doing, brother...

Teacher Xie’s classes are either heavenly books or cross talk. Isn’t it good to make good use of your time?

"Although this guy's aura doesn't match mine, he's quite interesting." Xie Qifen sighed, lighting the glass. "Scientific research all leads to the same goal by different paths. Although I should prefer Gui Jianfeng, his path can be regarded as a common one."

Let’s go.”

"!" Lu Yang trembled again, "Teacher Xie...are you praising him?"

"Didn't you hear that I thought he was stupid?" Jie Qifen curled his lips and said, "How can I possibly teach high school students? I'm just teasing him. I will definitely drive him home if he can't solve the questions when he debuts."

"Huh...that's right..." Lu Yang breathed a sigh of relief, "I'd say, you can best teach people like Gui Jianfeng."

"It depends on your mood."

"whee……"

"I never thought you deserved a beating before, did you?"

"I'm leaving now, I'm leaving now..."

…

In the classroom, Li Zheng, relying on the residual heat of his ascension, found a way to win, and soon came up with ideas for solving the problem.

What is the maximum amount of charge a drop of water can carry?

Easily, he sketched a physical image in his mind.

First, there is tension on the surface of the water droplet, causing the droplet to shrink.

The charge on the surface of the droplet causes the droplet to expand due to repulsion.

When the repulsive force is equal to the tension, the water droplets will not be able to maintain their shape and will then break.

The amount of charge that generates repulsive force at this time is the maximum amount of charge.

After figuring out the principle, Li Zheng started writing.

In the absence of the influence of gravity in a vacuum, assume that the water droplet is spherical, with a radius r, a density p, a surface tension coefficient σ, a charge carrying amount q, and a vacuum dielectric constant e.

Then according to the "cutting analysis method" we just learned, take a small microelement on the water drop and conduct force analysis...

Micro for a moment...

Slightly a little longer...

No, draw a geometric diagram...

Damn it, go up to the curvature...

…

Appeared!

The tension is 2σ/r!

The style must be so handsome.

And then there’s the repulsion…

Cut into pieces and mince.

No matter, differential is heaven in fluid mechanics.

Then calculate the electric field strength...

Hmm... I feel like I'm going to learn Gauss's theorem here...

So finally...

The repulsive force is 1/2·e(q/4πer2)2!

Let the repulsion and tension be equal in magnitude and solve the equation...

Appeared!

q=8π√er3σ!

To put it simply, by the time Li Zheng actually finished it, he was already sweating profusely, and Xie Qifen was just holding his watch and pushing the door open to return to the classroom.

He walked all the way to Li Zheng, squinted and picked up the answer sheet.

Then there was a glare.

"Fuck you, did you really do it?"

"Humph, isn't it difficult..." Li Zheng smoothed out his watery hibiscus-like hair, "Can you start telling me about your research?"

"It's not...this..." Jie Qifen searched for a long time but couldn't find a flaw. He scratched his head irritably, "I haven't finished the question, so this is the first question."

"??!" Li Zheng stood up in shock.

Damn you! You idiot!

"Don't worry, don't worry, the second question is also very simple." Jie Qifeng reassured, "Listen up, the second question - please use another method to solve the problem."

"???"

"Broaden your mind, take half an hour."

Jie Qifen just closed its doors and left.

Li Zheng was naturally very angry.
To be continued...