# Electromagnetic Waves Assignments/DPPs

The captivating world of Physics takes a luminous turn as we delve into the chapter “Electromagnetic Waves” for Class 12. This chapter unlocks the secrets behind the invisible waves that permeate our universe, from radio waves to visible light, crucial for success in both JEE and NEET. It unveils the fascinating relationship between changing electric and magnetic fields, and how they travel through space as self-propagating waves, shaping the world around us.

## Overview : Electromagnetic Waves for Class 12 JEE and NEET

“Electromagnetic Waves” introduces the concept of EM waves, a disturbance that propagates through space and time, consisting of oscillating electric and magnetic fields perpendicular to each other:

• Static Fields vs. Electromagnetic Waves: Static electric and magnetic fields exist independently. However, a changing electric field generates a changing magnetic field, and vice versa. This creates a self-propagating wave that doesn’t require a medium for transmission (unlike sound waves).

Properties of Electromagnetic Waves:

The chapter explores the key properties of EM waves:

• Electric and Magnetic Field Components: EM waves consist of an electric field (E) and a magnetic field (B) oscillating in phase and perpendicular to each other. These fields travel together as a wavefront.
• Speed of Light (c): EM waves travel in a vacuum at a constant speed, the speed of light (c), approximately 3 x 10⁸ m/s. This speed is a fundamental constant in physics.
• Wavelength (λ) and Frequency (f): The distance between consecutive crests of the wave is the wavelength (λ). The number of wave cycles per second is the frequency (f). They are related by the equation c = λf.

The Electromagnetic Spectrum: A Symphony of Waves

“Electromagnetic Waves” unveils the electromagnetic spectrum, a vast range of EM waves categorized by their frequency and wavelength:

• Radio Waves: Lowest frequency and longest wavelength, used for communication, broadcasting, and heating.
• Microwaves: Higher frequency than radio waves, used in microwave ovens, radar systems, and satellite communication.
• Infrared Radiation: Even higher frequency, invisible to the naked eye, used in night vision devices and remote controls.
• Visible Light: A narrow range of frequencies perceived by the human eye as different colors.
• Ultraviolet Radiation: Higher frequency than visible light, can cause sunburn and is used for sterilization.
• X-rays: Very high frequency and short wavelength, used in medical imaging and security scanners.
• Gamma Rays: Highest frequency and shortest wavelength, highly energetic and ionizing, used in cancer treatment and nuclear physics.

Understanding Wave Behavior:

The chapter explores core concepts of wave behavior like reflection, refraction, and diffraction:

• Reflection: When an EM wave encounters a surface, it can bounce back, following the law of reflection (angle of incidence equals angle of reflection).
• Refraction: As an EM wave travels from one medium to another (e.g., air to water), its speed and direction can change, causing bending of the wavefront (e.g., why a straw appears bent in a glass of water).
• Diffraction: When an EM wave encounters an edge or a narrow opening, it can bend around the obstacle and spread out.

Applications of Electromagnetic Waves:

EM waves have numerous applications across diverse fields:

• Communication: Radio waves, microwaves, and satellites enable communication technologies like radio, television, and mobile phones.
• Medical Diagnosis and Treatment: X-rays and gamma rays are used in medical imaging for diagnosis and cancer treatment, respectively.
• Scientific Research: EM waves across the spectrum are used in various scientific studies for material characterization, astronomical observations, and spectroscopy.
• Domestic Applications: Microwaves for heating food, infrared lamps for heating, and ultraviolet light for disinfection are some everyday examples.

## DPPs for Electromagnetic Waves

Mastering Electromagnetic Waves for JEE & NEET Success:

Conquering the intricacies of “Electromagnetic Waves” empowers you to excel in both JEE and NEET. Here’s how you can elevate your preparation:

• Focused Assignments: Solidify your understanding by tackling dedicated exercises from PRERNA EDUCATION. Focus on specific topics like properties of EM waves, electromagnetic spectrum, wave behavior (reflection, refraction, diffraction), and applications of EM waves.

• Daily Practice Problems (DPPs): Hone your problem-solving skills and build speed by tackling daily practice problems (DPPs) encompassing diverse concepts like:

• Calculating wavelength and frequency of EM waves based on their speed.
• Applying concepts of reflection and refraction to solve problems involving mirrors, lenses, and optical phenomena.
• Utilizing your knowledge of the electromagnetic spectrum to explain the applications of different types of EM waves in various fields.

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