Problem 48 - A Complete Resource Book in Chemistry for JEE Main

Question

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

Step-by-Step Solution

Answer

The correct answer is (a) radiowave.

Step 1: Understanding Electromagnetic Spectrum

The electromagnetic spectrum contains different types of electromagnetic radiation, such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. Each type has a different range of wavelengths.

Step 2: Identifying Wavelength Ranges

Radio waves have the longest wavelengths in the electromagnetic spectrum, ranging from about 1 millimeter to more than 100 kilometers. Other types of radiation like X-rays, infrared, and ultraviolet have shorter wavelengths than radio waves.

Step 3: Comparing Wavelengths of Options

Among the options given: (a) radiowave, (b) X-ray, (c) infrared, (d) ultraviolet, radiowaves have the maximum wavelengths, followed by infrared, ultraviolet, and X-rays, which have the shortest wavelengths.

Step 4: Selecting the Correct Answer

Given that radiowaves have the maximum wavelengths in comparison to the other options, choice (a) radiowave is the correct option.

Key Concepts

Wavelengths of Electromagnetic Waves

The electromagnetic spectrum is a collection of various types of electromagnetic radiation, each characterized by different wavelength ranges. Wavelengths in this context refer to the distance between successive peaks of the wave.

• Radio waves sit at one end of the spectrum with the longest wavelengths. These can be as short as 1 millimeter or stretch beyond 100 kilometers.
• Moving across the spectrum, microwave, infrared, visible light, ultraviolet, X-rays, and gamma rays each represent smaller wavelengths.

Understanding the distribution of wavelengths helps in identifying and distinguishing types of electromagnetic radiation. Each range of wavelengths is associated with different frequencies and, therefore, varies in energy levels.

Types of Electromagnetic Radiation

The electromagnetic spectrum is vast and diverse, comprising several types of electromagnetic radiation. Each type has unique applications and characteristics.

• Radio Waves: Known for their long wavelengths, they are widely used in broadcasting and communications.
• Microwaves: Utilized for heating food and in radar technology, they have shorter wavelengths than radio waves.
• Infrared Radiation: Commonly associated with heat, this radiation type is used in thermal imaging and remote controls.
• Visible Light: The only part of the spectrum visible to the human eye, ranging from red light (longer wavelength) to violet (shorter wavelength).
• Ultraviolet (UV) Light: Beyond visible light, UV rays are instrumental in sterilizing medical equipment but can also be harmful in excessive exposure.
• X-rays: With even shorter wavelengths, they are crucial in medical imaging.
• Gamma Rays: Possessing the shortest wavelengths and highest energy, they are used in cancer treatment and studying nuclear reactions.

Each type of radiation serves a distinct purpose in scientific and everyday contexts, distinguished by their wavelength and energy.

Properties of Radio Waves

Radio waves are a fundamental part of our connected world, underpinning various technologies and communications.

• Long Wavelengths: Their large wavelength range, from 1 millimeter to over 100 kilometers, allows them to travel long distances and penetrate through walls and other obstacles.
• Low Energy: Despite their extensive reach, radio waves carry low energy, making them safe for general use and not harmful to human tissue.
• Frequency Bands: They are divided into different frequency bands, each used for specific purposes — from AM and FM radio to television and mobile networks.
• Applications: Beyond communication, they are used in radar for navigation and in studying cosmic phenomena at astronomical scales.

These properties make radio waves indispensable for modern life, facilitating everything from listening to music on the morning commute to exploring the universe.