The question asks to identify the specific frequency range allocated for AM radio broadcasting. Understanding different radio frequency bands is fundamental to comprehending how various communication technologies operate.

AM Radio Frequency Basics

AM radio stands for Amplitude Modulation. It is a broadcasting method where the amplitude (strength) of a radio carrier wave is varied in proportion to the audio signal being transmitted. This technique allows voice and music to be sent over long distances. The frequencies used for AM radio are part of the medium wave (MW) band of the electromagnetic spectrum.

Different types of radio transmissions, like AM radio and FM radio, operate within distinct frequency ranges. These ranges are standardized globally to prevent interference and ensure efficient use of the radio spectrum.

Analyzing AM Radio Frequency Options

Let's evaluate each given option to pinpoint the correct frequency range for AM radio:

• 88 MHz to 108 MHz: This frequency range is primarily used for FM (Frequency Modulation) radio broadcasting. FM radio offers higher audio fidelity compared to AM radio and operates in the Very High Frequency (VHF) band.
• 535 kHz to 1605 kHz: This is the internationally recognized and most common frequency range for AM radio broadcasting in the medium wave band. Radio stations using Amplitude Modulation typically transmit within these kilohertz (kHz) frequencies.
• 20 Hz to 20 kHz: This range represents the approximate limits of human hearing, also known as the audio frequency spectrum. It is not a radio broadcasting frequency band but rather the range of sound frequencies audible to the human ear.
• 3.2 GHz to 8.2 GHz: This very high frequency range falls within the microwave spectrum (Gigahertz - GHz). Frequencies in this band are used for applications such as satellite communication, Wi-Fi, radar, and cellular networks, not for conventional AM or FM radio broadcasting.

Kilohertz (kHz) vs. Megahertz (MHz) in Radio Frequencies

It is important to distinguish between kilohertz (kHz) and megahertz (MHz) when discussing radio frequencies:

• Kilohertz (kHz): One kilohertz is equivalent to 1,000 hertz (Hz). Lower radio frequencies, like those used for AM radio and longwave transmissions, are typically measured in kilohertz.
• Megahertz (MHz): One megahertz is equivalent to 1,000,000 hertz (Hz), or 1,000 kilohertz (kHz). Higher radio frequencies, such as those for FM radio, television broadcasts, and many wireless communication systems, are measured in megahertz.

The AM radio frequency range is comfortably within the kilohertz scale, classifying it as a medium wave broadcast.

Based on the standard allocations for radio broadcasting, the correct frequency range for AM radio is 535 kHz to 1605 kHz.