Interview (4)
“Energy is supplied to the light bulb by the field.”
“The field?”
“Yes. The electromagnetic field.”
I wrote a single equation on the board.
“This is the Poynting vector.”
“…Poynting vector?”
“It is the vector related to energy transport in the electromagnetic field.”
The two interviewers glanced at each other and shrugged. Neither of them looked pleased. Except for one.
“Can you explain what a vector is?”
The interviewer seated farthest to the right nodded with interest.
“Of course.”
I answered confidently.
“A vector is a physical quantity that possesses both magnitude and direction. However, that is not the precise definition. More mathematically, an element of a vector space can be called a vector.”
“Uh…”
“But that is not our concern here. In physics, we define a vector as a physical quantity that transforms under coordinate transformations, such as position.”
“Oh dear.”
The longer I spoke, the more the two interviewers frowned. But it was too late. There was no stopping my explanation once momentum had taken hold.
“Returning to the main point, both the electric field and the magnetic field are fields. A field is a function whose domain is the position vector. At every location, we can establish a one-to-one correspondence with the information of electric and magnetic forces. From this fact, we can determine the direction in which electromagnetic energy is transported at every point. This is where the Poynting vector appears.”
I explained calmly and continued drawing. Electric field lines first, then the changing magnetic field lines overlaid upon them. The electronic board, which had contained only a few equations, now displayed a complex and subtle field. Drawing it quickly and accurately was a difficult process, yet it did not take me long. Because—
“Ah, no, that…”
I had used both hands.
After finishing the diagram, I turned around.
“This is a diagram representing the strength and direction of the field.”
When I looked around, the expressions of the two interviewers were far from favorable. They were frowning as though they desperately needed the restroom. What? Had I drawn it wrong? No, the diagram was correct.
“Hahaha.”
Amidst it all, only the interviewer on the right laughed. I knew instinctively. That person was different. At the very least, the atmosphere he gave off was the complete opposite of the other two interviewers. Not a teacher, but the bearing of a professor. My radar, honed from half a lifetime of serving as a professor’s assistant, was quite accurate. I could distinguish scholars from non-scholars at a glance. Therefore, even without knowing his face, I could tell. That person was surely the one I had been looking for.
“……”
I needed to make a good impression on him. I steadied my breathing. After finishing my notes, I set down the electronic pen and continued the explanation. Let me see, where had I left off?
“The Poynting vector…”
That was it.
“The direction perpendicular to the electromagnetic field is precisely the direction of the Poynting vector. Energy is transmitted in that direction. The method to determine this is simple. We use the right-hand coordinate system.”
“Ha, student.”
“Here, what is the right-hand coordinate system? Well, it is a coordinate system based on the manner of curling the right hand like so.”
“Ha, student. That is enough. Now stop…”
“Curl your fingers from the electric field toward the magnetic field, and point your thumb in the direction of the Poynting vector. No matter which point you calculate from, the direction of energy will converge on the light bulb. And…”
“Excuse me, student?”
“…The propagation speed of this electromagnetic field is equal to the speed of light. Suppose I place the battery and switch here in Stellarium, and the light bulb in the northern Adelbein planetary system. Ignoring the black holes in between, the straight-line distance is eighty thousand light-years, so if I flip the switch here, the bulb would only light up after eighty thousand years……”
“Student—!!”
“Y-yes?”
Deeply immersed in my explanation, I closed my mouth at the interviewer’s shout. I still had a little more to say.
“That is quite enough. It is more than sufficient!”
“But I have not yet…”
“It is fine!!”
The interviewer waved his hand frantically. It seemed the interview time was nearly over.
“Did you not say just moments ago that you had not studied ahead?”
“No, I did not.”
Since there was no record, it was correct that I had not.
“The explanation you just gave seems to exceed the academy curriculum?”
Ah. Right. This was not a graduate school interview. In my eagerness to impress the interviewer on the far right, I had unnecessarily lengthened my explanation.
“……I looked it up out of personal curiosity.”
I made a suitable excuse. The two interviewers were already wiping their foreheads with handkerchiefs. Sweat poured down their brows like rain. Strange. The heater did not seem turned up that high. In any case, I returned to my original posture and prepared for the next question. They would probably ask about future plans or motivation for applying. While I was repeating the prepared lines in my head, the interviewer on the far right pointed at the board and asked,
“Regarding that Poynting vector, do you know how it is derived?”
“Of course.”
I could never resist explaining the derivation process.
“This one turned out to be more impressive than he looked. Not even belonging to our forces, yet driving two humans mad in an instant.”
— The God of Wisdom and Curiosity applauds you.
— You have received a donation of 5500 Fron!
Looking at the message floating in the air, I let out a hollow laugh.
“Damn it.”
I had overdone the interview. By turning into a motor-mouth in front of the interviewers, I had surely left a terrible impression. It was obvious even without seeing it. I had failed. Receiving a massive amount of Fron right now was useless. If I were rejected from Stellarium like this, the only remaining option would be to bear the child of an Outer God. Surely Cartesia had not given this as a dowry?
— The God of Wisdom and Curiosity smiles faintly.
Did I really need to prepare myself mentally?
“……”
No, I still did not know. Do what you can, and leave the rest to heaven. Since I had done everything possible, all that remained was to wait. While I waited anxiously in the waiting room after the interview, other students began to trickle in.
“How was the interview?”
And among them was Zernya. Seeing my constipated expression, she let out a seductive laugh and sat beside me.
“I can tell just by looking at your face.”
“……”
“See? I told you, didn’t I?”
Everything could flip in an instant. Hearing those words, I felt an urge to flip the entire place over. I finally understood why the Adelbein bloodline was described as having a foul personality in novels.
“Too bad.”
Zernya grinned. She seemed convinced of my rejection.
“Thank you all for your hard work. Please pack your belongings and return home.”
Since I was not certain, even the supervisor’s clichéd farewell did not sound welcome. I had thought I would at least feel happy once the entrance exam was over, but now I only felt emptiness. Whatever. Let it be what it will be. I grabbed my bag and left roughly. Then, feeling an urgent need, I turned toward the restroom.
“Oh my.”
There, I encountered an unexpected person.
“Hoho.”
It was the interviewer who had asked me consecutive major-related questions during the interview.
“So it was that student from earlier.”
I smiled awkwardly and bowed my head.
“It was an entertaining time. Though it did not feel like an interview at all. Hahaha.”
He adjusted his shirt while looking in the mirror. His somewhat disheveled appearance made him seem less like a teacher or professor and more like a sage who had transcended the affairs of the world.
“The evaluation itself ended on the spot. Your acceptance or rejection was probably decided right then and there.”
“Yes…”
“Still, if there is something I want to say out of concern… it is that you explained the Poynting vector in a manner that was too difficult.”
“…Did I?”
“Yes. Before diving into equations, practice cultivating intuition first.”
The interviewer pointed out the regrettable parts one by one. His level was far beyond reach. It was insight that could never come from academy teachers who had only skimmed the surface of science. It was the eloquence of an expert.
“If you had understood only the physical meaning, I would not have asked about the derivation process. Haha. When you mentioned that, the sight of the other interviewers panicking and trying to flee was quite a spectacle…”
“…Haha.”
It meant I should have spoken briefly and concisely so they would not get bored. Tap, tap. After washing his hands, the interviewer shook off the water lightly and continued.
“Student, your name was Eidel, correct?”
“Yes.”
“Do you know why we did not ask about your motivation for applying or your future aspirations during the interview?”
Motivation and future aspirations were almost always asked. I had prepared for them, yet in the end, the personality interview was skipped and only the major interview was conducted. I had thought the reason was that the interview time was insufficient.
“You are wrong.”
Apparently not.
“We did not ask because there was no need to.”
Once the long entrance exam schedule ended, I collapsed like a ghost.
“I am dying.”
“Have you not been overexerting yourself? It is only natural to feel unwell once the tension is released.”
Even as the era advanced, the human body hardly changed. Concepts like transhumanism might have emerged, but it seemed the author had not considered them. The genetic level of humanity was the same in reality and here. Therefore, the mechanisms by which humans contracted diseases were identical, and the methods of rest were not much different either. Sonia spoke while changing the wet towel for me as I lay in bed.
“Please give birth quickly.”
“Give birth to what…”
“Pardon me, it seems my vocal cords are due for replacement soon. Please recover quickly.”
The fever was no ordinary level. Even pressing a wet towel to my forehead for ten minutes made it quickly warm up again. Sonia placed the towel down once more. After wringing out the water, she touched my forehead with her hand. How embarrassing.
“Accurate measurement is difficult.”
With a rustle, Sonia stood up. She pressed her own forehead against mine. I felt a cool, yet warmer than steel, lukewarm sensation.
“A robot placing her forehead on a human’s head as she pleases.”
“Are you belittling my nursing, human?”
Sonia looked down at me while still pressing her forehead against mine. We were so close that our noses might touch if we were not careful.
“Move.”
“……”
“It is heavy, so move…”
“39.8 degrees.”
Only then did Sonia lift her forehead and pick up the towel. Plop! Unlike before, she placed the towel on my head without much care.
“You two are something else.”
And there was someone who had been watching this scene from beginning to end.
“When did you two become so close?”
It was Seti. She approached while glaring at us with displeasure. Thud. She held out a plain letter in front of me.
“This was lying in front of the door.”
“What is it?”
“I do not know either. It just had your name as the recipient. Who sends a plain handwritten letter in this day and age.”
“Could it be a love letter?”
“What? A love letter? Pfft, damn. Kuh, pfft, kuhup…! Ahahaha!!”
I lightly ignored the cackling Seti and tore open the letter. And there, written inside, was content I had not expected at all.
Additional interview. It is not mandatory, but if you wish, come to the address below at any time.
— A physics professor interested in you
Now I could be certain who the person I had met at the interview hall that day was. Yes… There was no one else who would play such a prank.