Problem 31 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Electromagnetic radiation with maximum wavelength is : (a) ultraviolet (b) radiowave (c) \(X\)-ray (d) infrared

Step-by-Step Solution

Answer

Radio waves have the maximum wavelength.

Step 1: Understanding Wavelength

Different types of electromagnetic radiation have characteristic ranges of wavelengths. Wavelength is defined as the distance between two peaks of a wave.

Step 2: Organizing Electromagnetic Spectrum

The electromagnetic spectrum includes various types of radiation in increasing order of wavelength: gamma rays, X-rays, ultraviolet, visible light, infrared, microwaves, and radio waves.

Step 3: Identifying Maximum Wavelength

Among the listed options, radio waves have the longest wavelength compared to ultraviolet, X-rays, and infrared radiation.

Key Concepts

Wavelength

Wavelength is a key concept in understanding the electromagnetic spectrum. It refers to the distance between consecutive peaks of a wave. This distance determines the wave's energy and its place in the electromagnetic spectrum. Waves with longer wavelengths have lower frequencies and energy, while waves with shorter wavelengths have higher frequencies and energy. Understanding wavelength is crucial because different types of electromagnetic radiation are classified based on this property. Therefore, knowing the wavelength allows us to categorize and understand how different types of radiation interact with the environment and with one another.
Additionally, wavelength is inversely proportional to frequency. This relationship is given by the equation: \[ c = \lambda \cdot f \]where \( c \) is the speed of light in a vacuum, \( \lambda \) is the wavelength, and \( f \) is the frequency.

Radio Waves

Radio waves are at the long-wavelength end of the electromagnetic spectrum. They have the longest wavelengths and the lowest frequencies compared to other types of electromagnetic radiation. This makes them exceptionally interesting and useful in communication technology.
Here's why radio waves are crucial:

• They can travel long distances, making them ideal for communication.
• Radio waves are used for transmitting TV and radio broadcasts.
• They penetrate most materials easily, allowing signals to pass through buildings and obstacles.

Given their low energy, radio waves do not ionize materials, making them safe and widely applicable. Their long wavelength also means they are less affected by obstacles compared to shorter wavelength waves, which can be absorbed or reflected.

Types of Radiation

The electromagnetic spectrum consists of various types of radiation. Each type has distinct properties due to differences in their wavelengths and frequencies. Here's a brief overview of the main types:

• **Gamma Rays**: These have the shortest wavelengths and highest energy. They are used in medical treatments and scientific research.
• **X-Rays**: Slightly longer than gamma rays, X-rays are commonly used in medicine for imaging bones and other internal structures.
• **Ultraviolet (UV) Rays**: With wavelengths shorter than visible light, UV rays are responsible for causing sunburns but are also used in sterilization processes.
• **Visible Light**: This is the only part of the spectrum visible to the human eye. It allows us to see the world around us.
• **Infrared (IR)**: Longer than visible light, used in night-vision technologies and remote controls. It is also emitted by warm objects.
• **Microwaves**: Have longer wavelengths than infrared and are used in microwave ovens and for satellite transmissions.
• **Radio Waves**: Have the longest wavelength and are used in communication technologies as mentioned previously.

Understanding these types of radiation helps us comprehend how they are applied in everyday technology and science. Each type plays a crucial role in different technological advancements, from medical imaging to wireless communications.