NovelTags Chapter 142
Chapter 142
Why do you want to study physics?
With a smile on his face, Academician Lin looked at Cheng Hao in front of him and said.”Hello, Academician Lin, I’m Cheng Hao!”
Cheng Hao hurriedly said to Academician Lin in front of him.
Academician Lin stretched out a hand towards Cheng Hao, and Cheng Hao quickly held his hands together with Academician Lin.
After shaking hands.
“The people here are too messy, go to my office!”
With that said, Academician Lin turned and walked towards the office beside him. Cheng Hao and Dean Liu quickly followed Academician Lin’s back.
Soon, the three of them came to an office, a huge office, and there was no one there.
“Come, sit down wherever you want.”
After Academician Lin sat down in a seat next to him, he said to Cheng Hao and Dean Liu who were on the side.
After everyone was seated.
At this time, Academician Lin looked at Cheng Hao with a smile on his face and said, “Student Cheng Hao likes physics? Do you want to pursue a degree in physics?”
Cheng Hao hurriedly nodded towards Academician Lin in front of him.
“As far as I know, your talent in mathematics is even higher. I also read your proof of Zhou’s conjecture! It’s really well written!”
Academician Lin’s eyes were full of emotion, looking at Cheng Hao in front of him, his eyes were full of appreciation.
“It is a blessing that we have a math genius like you in China! Your talent in number theory is extremely high. If you can devote your mind to it, you might have a chance to solve the crown of number theory. Riemann conjectures How can you think about distracting yourself to physics?
Physics is not that simple. Once you are distracted by physics, you may not be able to devote yourself to mathematics! In the end, the height you can reach in mathematics may be extremely limited! ”
Academician Lin looked seriously at Cheng Hao in front of him and said.
“As far as I know, I only know one person who can reach extremely high levels in both mathematics and physics, Edward Witten!
So, have you thought it through? ”
Academician Lin looked at Cheng Hao in front of him and asked.
After thinking about it seriously, Cheng Hao said to Academician Lin in front of him: “I have always felt that no matter what I study, it is ultimately for the advancement of science and for all mankind to climb the peak! Although mathematics is indeed the cornerstone of science, it can Solving mathematical problems is of great significance to the future development of science.
However, what I want to do is not just let mathematics develop, what I want more is to use my mathematics to guide the progress of science! ”
Seeing Cheng Hao’s serious eyes, Academician Lin looked at Cheng Hao in front of him with some surprise in his eyes.
“Good ambition!”
Academician Lin looked at Cheng Hao in front of him with some appreciation.
“Then since you want to take a degree in physics, have you also taught yourself physics? How are you doing?”
Academician Lin smiled slightly, looked at Cheng Hao in front of him and asked.
“Er…it’s okay…”
Cheng Hao hesitated for a moment, looked at Academician Lin in front of him and said.
“Haha! Then I’ll test you.”
With a smile in his eyes, Academician Lin said to Cheng Hao in front of him.
“Can!”
Cheng Hao nodded and agreed.
At this time, Academician Lin took a piece of paper and a pen from the side, and began to write on the table. Soon, Academician Lin wrote out a question.
Passed the question to Cheng Hao who was on the side.
“Come on, let’s see!”
With a smile on his face, Academician Lin said to Cheng Hao in front of him.
Cheng Hao quickly took the pen and paper from Academician Lin.
[A hydrogen atom in the ground state collides with another hydrogen atom in the resting ground state. What is the minimum speed at which an inelastic collision can occur? If the speed is large enough to emit light, and the light can be observed in the direction of the original speed. What is the difference between the frequency of this -27 light and the normal frequency?】
【The atomic mass of hydrogen is 1.67x10kg, the ionization energy E= 13.6eV, -18 2.18x10J. 】
Seeing the topic in front of him, Cheng Hao was slightly taken aback.
As expected of being an academician, it’s just different. This is not a test question for ordinary physics beginners. This is obviously a competition question, and it’s the kind of jumping around on the line.
But Cheng Hao was not intimidated by this question.
Looking at the question in front of him.
After thinking for a while, Cheng Hao had an idea.
[Analysis: The energy of the hydrogen atom in the ground state is E’=-E·(1/1^2), and the energy of the first excited state is E”=-E·(1/2^2). The minimum energy absorbed by a hydrogen atom is △E=E”-E’=E[1/(1^2)-1/(2^2)]=3/4E=1.163*10^-18(J) 】
[We must find out the minimum speed at which the energy loss in the collision is equal to the above data. If the collision is completely inelastic, the energy loss in the collision will be the largest, the speed after the collision will be v/2, and the initial kinetic energy and final kinetic energy will be: mv^2)/2-[2m(v/2)^2] /2=(mv^2)/4, this value should be equal to the smallest energy quantum △E=(mv^2)/4,
Therefore v=√(4△E/m)=6.26*10^4(m/s)
After the inelastic collision, the velocity of the two atoms is v/2= 3.13x104m/s
The answer to the second question is related to the Doppler effect. For velocities much smaller than the speed of light, the ratio of relative velocities gives an excellent approximation of the relative change in frequency: 6.26*10^4:3*10^8=2.09*10^-4=2.09*10^-2%
The frequencies of the two beams of light are compared according to thisrate is slightly less than or slightly greater than the normal frequency. 】
Cheng Hao’s topic was written in great detail. Academician Lin beside him couldn’t help but nod his head, and the admiration in his eyes when he looked at Cheng Hao grew stronger.
“Academician Lin, I figured it out!”
Cheng Hao handed the paper to Academician Lin beside him.
Academician Lin took the paper without looking at it. Looking at Cheng Hao in front of him, he smiled slightly and said, “The solution is not bad. It can be seen that the basic skills are still good! The learning ability is very strong!”
Cheng Hao smiled honestly, scratched his head, and didn’t say much.
At this time, Academician Lin in front of him suddenly said to Cheng Hao in front of him, “Recite Kennan’s expression of the second law of thermodynamics.”
Cheng Hao was stunned for a moment, but he quickly remembered this knowledge point.
“For a system with given energy, material composition, and parameters, there is such a stable equilibrium state: other states can always be reached through reversible processes.”
Cheng Hao opened his mouth and came directly.
Hearing Cheng Hao’s words, the satisfaction in Academician Lin’s eyes became more and more intense.
“All right! The basic skills are very solid, not bad!”
Academician Lin nodded in satisfaction.
“Okay! I have no problem here!”
Academician Lin smiled and asked Cheng Hao, “Student Cheng Hao, do you have any questions about me?”