Which of the following is NOT electromagnetic waves?

Correct option is C

The correct answer is (c) Ultrasound.

• Ultrasound is NOT an electromagnetic wave. It consists of mechanical waves that require a medium (such as air, water, or solids) to propagate.
• These are high-frequency sound waves that cannot travel through a vacuum and are commonly used in medical imaging and industrial testing.

Information about the other Options:

• Radio: Radio waves are a type of electromagnetic wave that have long wavelengths and are used for communication, broadcasting, and wireless communication.
• Microwave: Microwaves are electromagnetic waves with shorter wavelengths than radio waves. They are used in radar, communication systems, and microwave ovens.
• Infra-red: Infrared radiation is part of the electromagnetic spectrum, with wavelengths longer than visible light. It is used in various technologies, such as thermal imaging and remote controls.

Information Booster:

Electromagnetic Waves:

• Electromagnetic waves, including light, are produced when electrically charged particles vibrate, leading to an energy transformation.
• These waves consist of electric and magnetic fields that oscillate at right angles to each other and the direction in which the wave travels.
• First discovered by James Clerk Maxwell and later confirmed by Heinrich Hertz, these waves travel at the speed of light and are capable of transmitting energy and information across a broad range of wavelengths, from radio waves to gamma rays.
• These waves do not require a medium to propagate and can travel through a vacuum.