Question

Range of frequency of microwaves is about (A) \(530 \mathrm{kHz}\) to \(1710 \mathrm{kHz}\) (B) \(54 \mathrm{MHz}\) to \(890 \mathrm{MHz}\) (C) \(3 \mathrm{GHz}\) to \(300 \mathrm{GHz}\) (D) \(4 \times 10^{14} \mathrm{~Hz}\) to \(7 \times 10^{14} \mathrm{~Hz}\)

Short answer

The correct range of frequency for microwaves is (C) \(3 \mathrm{GHz}\) to \(300 \mathrm{GHz}\).

Step-by-step solution

Understand Microwaves Frequencies

Microwaves are a type of electromagnetic radiation, and their frequencies fall within a specific range of the electromagnetic spectrum, between radio waves and infrared waves.

Evaluate Option A

Option A suggests a frequency range for microwaves between \(530 \text{kHz}\) and \(1710 \text{kHz}\). This frequency range actually corresponds to the Medium Frequency (MF) portion of the radio wave spectrum, which is mainly used for AM radio broadcasting. Thus, option A is incorrect.

Evaluate Option B

Option B gives a range of \(54 \text{MHz}\) to \(890 \text{MHz}\). This frequency range corresponds to the Very High Frequency (VHF) portion of the radio wave spectrum, which is used for FM radio broadcasting, television broadcasting, and other communication devices. This range is also not within the microwave frequency range, so option B is incorrect.

Evaluate Option C

Option C states a range of \(3 \text{GHz}\) to \(300 \text{GHz}\). This frequency range corresponds to the microwave portion of the electromagnetic spectrum. Microwaves are utilized in many applications such as communication, weather analysis, radar systems, and of course, microwave ovens. Therefore, option C is the correct answer.

Evaluate Option D (For completeness)

Option D gives a range of \(4 \times 10^{14} \mathrm{~Hz}\) to \(7 \times 10^{14} \mathrm{~Hz}\). This frequency range corresponds to the visible light portion of the electromagnetic spectrum and not to microwaves. Thus, option D is incorrect. In conclusion, the correct range of frequency for microwaves is: (C) \(3 \mathrm{GHz}\) to \(300 \mathrm{GHz}\)

Key concepts

Electromagnetic Spectrum

The electromagnetic spectrum is an essential concept in understanding waves and their applications. It encompasses all types of electromagnetic radiation, from low-frequency radio waves to high-frequency gamma rays. Each type of electromagnetic radiation has unique properties and uses, determined primarily by its frequency and wavelength. These waves all travel at the speed of light in a vacuum, but differ in frequency, wavelength, and energy. The spectrum is usually divided into subsets, each of which has different characteristics and applications in fields such as communication, medicine, and astronomy.

• Radio Waves: Lower frequency and longer wavelengths, used in communication.
• Microwaves: Higher frequency than radio waves, utilized in cooking and radar.
• Infrared: Used in remote controls and thermal imaging.
• Visible Light: The only part of the spectrum visible to the human eye.
• Ultraviolet: Can cause sunburn and is used in sterilization.
• X-Rays: Used in medical imaging.
• Gamma Rays: Highest frequency and energy, used in cancer treatment.

Radio Waves

Radio waves are a fascinating and practical subset of the electromagnetic spectrum. They have the longest wavelengths and the lowest frequencies of all electromagnetic waves, ranging from tens of meters to kilometers. This makes them particularly effective for transmitting data over long distances without significant loss of strength. Radio waves are commonly used in many aspects of daily life, such as:

• Broadcasting audio signals in AM and FM radio
• Television broadcasting to deliver content to homes
• Wi-Fi and Bluetooth technologies for wireless communication
• Radar systems used in aviation and weather forecasting
• Cellular networks enabling mobile phone communication

Because of their wide application, radio waves play an integral role in communication technologies, making it easier to connect and share information across the globe.

Visible Light

Visible light is perhaps the most familiar portion of the electromagnetic spectrum. It is the range of electromagnetic radiation that human eyes can detect, making up just a small segment of the overall spectrum. The frequencies of visible light range from approximately \(4 \times 10^{14} \mathrm{~Hz}\) to \(7 \times 10^{14} \mathrm{~Hz}\), corresponding to wavelengths from about 400 to 700 nanometers.This range includes all the colors of the rainbow, with each color having a different frequency and wavelength:

• Red has the longest wavelength and lowest frequency.
• Orange follows red with a slightly shorter wavelength.
• Yellow, familiar for its bright hue, follows orange.
• Green lies in the middle of the visible spectrum, balancing energy and wavelength.
• Blue and indigo are shorter wavelengths, associated with lucid skies and oceans.
• Violet completes the spectrum with the shortest wavelength, thus highest frequency in visible light.

Visible light is crucial for human vision, enabling us to perceive and interact with our environment. Understanding this segment of the spectrum helps in technologies such as cameras, lighting, and optical instruments.