I just want to be a quiet scholar

Chapter 99 Steady progress on the road of pretending

"Before, I didn't have a choice. Now, I just want to be a quiet scholar." Shen Qi said from the bottom of his heart.

"Just pretend to be quiet, Mr. Shen Qi!" The boy wiped his tears and stopped crying. The boy should be self-improvement. He asked, "By the way, how much did you score in the theory test this time?"

"280."

"I...I'm already seriously unwell...I want to report you, Shen Qi!" The boy slammed a punch on the tree next to him.

"Please don't do this, my friend." Shen Qi stood up and turned to leave.

"Wait a minute, boss!" The boy grabbed Shen Qi's arm and said eagerly, "Do you have a pen on you? The pen from yesterday's exam."

Shen Qi had a pen in his pocket, which Mu Rong gave him when filling out the form just now, but Mu Rong forgot to take it.

"Here, I'll give it to you." Shen Qi took out the water-based pen and handed it to the boy.

"Thank you, boss!" The boy took Shen Qi's pen and swept away the slump: "With the magic pen in hand, you will have no worries about the exam! Mr. Shen Qi, I wish you steady progress on the road of pretending to force, and you will be promoted to Yanda as soon as possible. A new generation to force the king!"

……

The next day, the CPhO experiment was in progress.

80 points for experimental questions and 280 points for theoretical questions.

Experiment + theory is the total score of this national final.

Shen Qi got a perfect score of 280 in the theory test the day before yesterday. As long as he doesn't make low-level mistakes in today's experiment, his total score will enter a higher range.

Why did the contestant from the Suzhou-Hangzhou No. 172 Middle School that I met yesterday cry, because his theoretical score was only 80. Even if the experiment got a perfect score of [-], his total score could not be higher than Shen Qi's theoretical score.

The theory test is of course the highlight of the national finals, but the experimental questions cannot be slack.

All contestants are divided into two groups, one in the morning and one in the afternoon. The morning and afternoon test questions are all electrical experiments, with different questions but similar difficulty.

Shen Qi's draw was to do an experiment in the afternoon.

The experimental instruments and utensils issued by the invigilator are:

1 DC stabilized power supply, 2 digital multimeters, 2 potentiometers, 1 standard resistance box, 1 DC galvanometer, 1 constant temperature water bath, 1 diode to be tested, [-] programmable calculator, lead wire some.

The experimental requirements are:
Design an experiment based on a given experimental instrument to accurately measure the forward volt-ampere characteristics of the diode at t=27°C.The variation range of the current is 0.5-1000μA, and no less than 20 sets of data are required to be measured.

And, draw a circuit diagram, explain the experimental principle, write out the experimental steps, and design a table to record the experimental data.Also draw the forward volt-ampere characteristic curve of the diode to obtain the reverse saturation current I0 and the ideality factor n.

If you have completed the steps described above and got the correct result, it is not over yet, please continue:
When the current in the diode is constant, set the current of the diode to be 5μA, 15μA, and 20μA respectively, try to determine the relationship between the voltage and temperature, deduce the diode voltage Vg(0) at absolute zero, and analyze under different constant current conditions , the characteristics of the diode forward junction voltage obtained at absolute zero and its causes.

The above is the question stem requirements given on the experiment answer sheet.

This experimental question is not difficult, but it is not so easy to get all 80 points. In addition to the accuracy of the steps and results written on the answer sheet, the practical behavior of the players is also counted in the scoring or deduction items.

The invigilator inspects the laboratory and records the practical behavior of each contestant. One-on-one marking is impossible, and there are not so many invigilators.Usually, an invigilator is staring at a few players around, so today's experimental session is divided into two sessions in the morning and afternoon, and the players are divided.

Shen Qi has practiced and practiced electrical experiments under the guidance of Mu Rong.

The experimental questions in the semi-finals are also electricity, and the finals are still.

Because the electrical experimental equipment is simple and easy to obtain, the experimental results can be verified on the spot, and it is easy to set up a competition experiment.

Each contestant has a particle accelerator, and the Chinese Physical Society does not have the ability and financial resources to organize it. The Chinese Physical Society headquarters only has a particle accelerator, which is still second-hand.

Shen Qi first used the bridge method to draw the measurement circuit diagram, and then set the temperature of the water bath to 27 degrees.

Connect the circuit according to the circuit diagram, adjust the initial value of the potentiometer so that the output voltage of the voltage divider circuit is 0, set the value of the resistance box to 1 Ω, and adjust the galvanometer to zero.

After completing these basic experimental preparations, Shen Qi turned on the power and slowly adjusted the potentiometer to increase the reading of the ammeter.

Continue to adjust and repeatedly adjust the potentiometer and resistance box, so that the bridge is in balance at the set voltage value.

Then Shen Qi drew a record form on the answer sheet to record the data.

Voltage 0.430V, current 0.52μA
Voltage 0.441V, current 0.77μA
……

记录了20组数据，沈奇根据这些数据画出二极管正向伏安特性曲线，计算出反向饱和电流I0=3.397×10^-14A，以及理想因子n=1.001。

The first small part of this experiment is done.

Up to this point, high school students need to master the basic electrical experiment operations, as well as the basic abilities of data recording, processing, and computing.

Therefore, the experimental part can't improve the score, not to mention the physical competition players, the ordinary high school students, the kind of so-so physics scores, the hands-on ability is just okay, it is no problem to finish the first small part of the national final experimental questions.

The second part is a little more cumbersome.

Derive the diode voltage Vg(0) at absolute zero, and analyze the characteristics and causes of the diode forward junction voltage at absolute zero obtained under different constant current conditions. This is actually a theoretical derivation calculation problem.

CPhO exams come and go, to put it bluntly, it is to test theoretical knowledge.

经过理论推导计算，沈奇得出Vg（0）在无限接近绝对零度时的值为1.225V、1.233V、1.244V，这三个电压值分别对应5μA、10μA和15μA的电流值。

The experimental part ends here.

Many contestants, including Shen Qi, successfully completed the experiment and answered the questions.

The scores of the test questions are announced on the same day.

None of the contestants got a perfect score for the 80-point experiment, and the highest score was 79.5.

In this part of the practical operation, each contestant was more or less deducted a point.

This is impossible. There is no standard posture for practical actions, and no one can guarantee that every detail of their own is perfect.

Shen Qi's experimental score got 77 points, and 3 points were deducted.He can accept the result.

The experimental scores are out, which means that the total score of this CPhO national finals has been finalized.

The Chinese Physical Society announced the total score ranking of the players:

1. Shen Qi (Nangang No. 357 Middle School), [-] points;
2. Tang Mengqi (Changjun Middle School), 352.5 points;
3. Su Xiaolie (No. 352 Middle School of Chinese Normal University), [-] points;
4. Lu Huaisong (Suhang No. 350.5 Middle School), [-] points;
5. Ma Zixin (Yali Middle School), 349 points;
5. Han Xuance (Shijia Village No. 349 Middle School), [-] points

7. Jin Shengqiang (Special Zone Middle School), 348.5 points;
……

200. Zeng Luna (Northeast Yucai School), 112 points.

总分成绩只公布到前200名，其中前50名获得全国一等奖，51-200名获得全国二等奖，201-412名都是三等奖。

The national gold medal score line is 282 points, which is the score of the 50th-ranked player.

The national training team scored 298 points, which is the score of the 40th-ranked player.

After the dust settled, 50 players won the first national gold medal, of which the top 40 gold medalists were selected for the national training team for the competition.

As in previous editions, the top 50 players are basically from domestic strong schools in physical competition and academic competitions.

Except for Shen Qi, who ranked first.

(End of this chapter)