Electromagnetic Waves Test - 1

Infrared radiation was discovered in 1800 by William Herschel.

When the sound waves propagate into the liquid media, it results in alternating high-pressure (compression) and low-pressure (rarefaction) cycles, whose rates depend on the frequency. During the low-pressure cycle, high-intensity ultrasonic waves create small vacuum bubbles or voids in the liquid. When the bubbles attain a volume at which they can no longer absorb energy, they collapse violently during a high-pressure cycle. This phenomenon is termed as cavitation.

Infrared radiations are used in the treatment of muscle aches.

A wavelength is the horizontal distance between the two peaks of the wave. Light is measured by its wavelength (in nanometers). It is usually characterized by the Greek symbol λ. Visible light is usually defined as having wavelengths in the range of 400–700 nanometers (nm) or one billionth of a meter.

The electromagnetic theory of light was developed by Maxwell.

The transverse nature of the electromagnetic radiation can be demonstrated by Polarisation experiment

The velocity of electromagnetic radiation in free space is 3 * 10⁸ ms^–1

Radio waves and visible light have same velocity.
The wavelength of radio waves (≈ 10 - 10³ m) is more than the wavelength of visible light (≈ 10^-7 m).

The visible region lies between 400 nm and 700 nm.
Speed of light, c = 3 × 10⁸ m/s
Using c = λf, the frequency range of the visible spectrum will be 4 × 10¹⁴ Hz to 7.5 × 10¹⁴ Hz.