Alternating current with a frequency of 1 million \(\mathrm{Hz}\) flows ina. wire. What in particular could be detected traveling outward from the wire?

Alternating current (AC) is a type of electrical current that changes direction periodically. Unlike direct current (DC), where electrons flow in a single direction, AC's flow of electrons reverses direction back and forth. This is the type of electricity typically supplied to homes and businesses.

One of the key characteristics of AC is its frequency, which is the number of times the current changes direction per second, measured in hertz (Hz). In many parts of the world, the standard frequency of AC is 50 Hz or 60 Hz, but it can be much higher in other applications. For example, the problem at hand involves an AC with a frequency of 1 million Hz, which is considerably higher than what you would find in household electricity.

Radio waves are a type of electromagnetic radiation, which is a form of energy that travels through space at the speed of light. They are at the low-frequency end of the electromagnetic spectrum and are largely known for their use in communication technologies, such as television, radio, and mobile phones.

The wavelength of radio waves can vary from thousands of meters to a few centimeters. Due to their long wavelengths, radio waves can diffract around obstacles, providing wide coverage which is why they are so useful for broadcasting. The problem introduced involves a frequency that produces radio waves with a wavelength typical of the Very High Frequency (VHF) band. This band is particularly useful for FM radio and television broadcasts, as well as aviation communications.

The frequency of electromagnetic radiation is the number of waves that pass a point in space per second, and it is directly related to the wave's energy. The entire electromagnetic spectrum is a range of frequencies from low to high, including radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays.

Each type of electromagnetic wave has a characteristic range of frequencies. For example, visible light has a frequency range of about 430 to 750 terahertz (THz), much higher than the 1 MHz frequency mentioned in our problem. The frequency not only affects the type of radiation but also has practical applications, such as determining the bandwidth for communication signals.

The speed of light, often denoted by the symbol 'c', is a fundamental physical constant important in many areas of physics. Light always travels at a constant speed of approximately 299,792 kilometers per second (or about 300,000 km/s) in a vacuum. This speed is a cornerstone of the theory of relativity, which shows that the speed of light is the same for all observers, no matter their state of motion.

The exercise references the speed of light when calculating the wavelength of the electromagnetic waves produced by the alternating current. It's important to note that while light travels at this constant speed in a vacuum, it can slow down when passing through various mediums, such as water or glass.