The lecture began.
The professor entered the hall carrying a stack of papers and a thick textbook, placing them on the desk before heading to the blackboard.
The lecture hall of the Faculty of Science and Engineering was spacious, its walls adorned with technical diagrams and scientific charts.
On the desks before the students, laptops and notebooks lay open in preparation for two hours of focus and labor.
The professor wrote the title of the lesson on the blackboard.
“Maxwell’s Equations and Electromagnetic Wave Propagation.” Then he began explaining in a calm voice.
“As we know, electrical and magnetic phenomena were not always understood as a single unified phenomenon.
Initially, scientists studied electricity and magnetism as two separate branches.
However, with the development of physics in the nineteenth century, James Clerk Maxwell proved that the two fields are interconnected, and that light itself is an electromagnetic wave.” He began drawing a set of equations on the blackboard.
“Maxwell’s four equations describe the relationship between electric charges, currents, and electric and magnetic fields.
Among the most important conclusions scientists reached from these equations is that a changing electric field generates a magnetic field, and a changing magnetic field generates an electric field.” He paused briefly, then wrote an equation on the board describing the relationship between the speed of electromagnetic wave propagation and the constants of the medium.
“When we solve these equations in a vacuum, we obtain a constant speed approximately equal to the speed of light.
This discovery was a major turning point in our understanding of the nature of light.” Students were taking down notes.
Some were following the blackboard.
Others were recording the explanation on their laptops.
Yet Lily…
She sat before her notebook, pen held between her fingers, barely moving.
She heard the professor’s voice.
She saw the words and equations before her.
Yet her mind was somewhere else.
Adam.
She tried to regain her focus on the lesson.
She wrote a line of notes.
Then she stopped.
She found herself staring at the page without remembering what the professor had said moments earlier.
The scene from yesterday returned to her.
His silence.
The way their conversation had ended.
Then she remembered the morning.
The phone that remained turned off.
Why had he not turned it on until now?
Was he angry?
Was he avoiding her?
Or was there another reason?
She shook her head slightly, trying to dispel these thoughts.
She did not want to lose her concentration.
She was in the Faculty of Science and Engineering, and studies for her required complete attention.
Yet this time, the problem lay not in the difficulty of the equations.
Rather, her mind was occupied with something else entirely.
The professor continued his explanation.
He moved from Maxwell’s equations to their practical applications.
He spoke about wireless communications, antennas, and how electromagnetic waves are utilized to transmit information across distances.
“Every wireless device we use today—from mobile phones to satellites—relies on our understanding of these principles.
We do not transmit sound or data directly; rather, we convert them into electromagnetic signals that can propagate through a medium.” Students jotted down these points quickly.
As for Lily, she stared down at her notebook.
Then, absentmindedly, she wrote in the margin of the page: “Adam” She stopped immediately when she realized what she had done.
She looked at the name for a moment.
Then she closed the notebook slightly with her hand as if hiding it from herself.
She sighed quietly.
She knew she had to focus.
She knew she had to wait until the end of the lecture.
Yet despite all her attempts…
There was one question that constantly returned: Where was Adam?
The professor continued explaining, unaware that a portion of Lily’s attention was no longer inside the hall.
He transitioned from theoretical principles to the engineering applications of electromagnetic waves, explaining to the students how equations that appeared as mere symbols on paper transformed into everyday technologies surrounding them.
He wrote a series of mathematical relations on the blackboard, then stated: “When we study wave propagation, it is not enough merely to know that they exist.
We must understand how they move, how they interact with matter, and how they can be controlled.” He drew a sine wave moving through space.
“Any wave we have can be described by a set of fundamental properties.
There is wavelength, which is the distance between two consecutive points in the same phase, and there is frequency, which is the number of oscillations occurring within one second.” He pointed to the drawing.
“The relationship between them is simple: propagation speed equals frequency multiplied by wavelength.
In a vacuum, for electromagnetic waves, this speed is the speed of light.” Some students began asking questions.
One student asked why the speed of light in glass differs from that in a vacuum.
The professor smiled and answered: “Light does not slow down because photons simply stop between atoms as some believe; rather, the electromagnetic field interacts with the charges within the material, and this interaction alters the overall propagation speed of the wave.” He continued discussing the refractive index, explaining how the direction of a wave changes when passing from one medium to another.
He detailed Snell’s Law, then moved on to total internal reflection and how it is utilized in optical fibers to transmit data over long distances.
“When we use the internet via optical fibers, we rely on a principle that is simple yet profound.
Light remains trapped inside the fiber due to repeated reflection, allowing vast amounts of information to be transmitted at high speed.” His words reached Lily.
Yet they did not settle in her mind.
She heard the sounds around her as though coming from a far-off place.
The sound of pens on paper.
The movement of students.
The voice of the professor explaining.
Everything was present.
Yet her thoughts returned every time to Adam.
She imagined the moment of their meeting.
Would he smile when he saw her?
Would he let her speak?
Would he be angry?
She replayed in her mind the words she had planned to say to him.
“I am sorry.” A simple sentence.
Yet it felt harder than expected.
Because she was not merely apologizing for a situation that had occurred.
She was apologizing for a feeling she had caused him to feel.
For a moment in which he might have felt she did not trust him.
Lily tried to return to the lecture.
She looked at the blackboard.
She saw the professor drawing a diagram of an electronic circuit containing a signal source, an antenna, and a receiver.
He was explaining how an electrical signal transforms into an electromagnetic wave propagating through space, only to be received by another device that converts it back into intelligible information.
“In engineering systems, we care not only about sending the signal, but also about its quality.
There is always noise and interference affecting the signal, which is why we use various techniques to improve the signal-to-noise ratio.” He wrote a term in English on the blackboard: Signal-to-Noise Ratio He explained to the students that any real-world communication system must handle numerous factors that can degrade data quality.
He discussed modulation, how information is loaded onto a carrier wave, and the distinction between amplitude and frequency modulation.
These were concepts Lily usually loved.
She enjoyed understanding the mechanics behind how things worked around her.
Yet today…
She could not grant them her full attention.
She held her pen and tried to write notes.
She wrote several lines.
Then she stopped.
She found that she had written an incomplete equation.
She looked at it for a moment, then capped her pen.
She knew this was not normal for her.
She rarely allowed anything to distract her from her studies.
Yet today was different.
Today, something awaited her after the lecture.
Someone she was waiting to see.
The professor continued his explanation.
He moved on to discuss antennas, and how their design depends on wavelength and operational frequency.
He explained that an ideal antenna is often linked to half the wavelength, and that changing the dimensions of the antenna affects its efficiency and capability to transmit and receive.
He then addressed its applications in mobile phones and modern communication networks.
Yet for Lily, one single question overshadowed all this information: Would Adam be at the university when the lecture ended?
She looked for a moment at the clock hanging on the wall.
There was still time left.
She sighed quietly, then tried once more to focus.
She did not wish to waste the entire lecture.
Yet no matter how hard she tried…
Her mind always drifted back to the exact same point.
Adam.