Question

Which of the following electromagnetic wave has the least wavelength? (A) radiowave (B) visible wave (C) ultraviolet rays (D) microwaves

Short answer

The electromagnetic wave with the least wavelength among the given options is (C) ultraviolet rays.

Step-by-step solution

Remember the electromagnetic spectrum

The electromagnetic spectrum is the range of all types of electromagnetic waves, ordered by their frequency and wavelength. It includes radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. The order of the waves in the spectrum is important for comparison.

Identify the order of the given waves

According to the electromagnetic spectrum, the order of the given waves from largest to smallest wavelength is: 1. Radiowaves 2. Microwaves 3. Visible waves 4. Ultraviolet rays

Determine the wave with the least wavelength

As we can see from the order of the waves in the spectrum, the wave with the least wavelength among the given options is ultraviolet rays.

Choose the correct answer

Now that we have determined the wave with the least wavelength, we can choose the correct answer from the options provided. The answer is: (C) ultraviolet rays

Key concepts

Electromagnetic Waves

Electromagnetic waves are fascinating forms of energy that travel through space at the speed of light. These waves are generated by the movement of electric and magnetic fields. They can move through a vacuum, meaning they do not need a medium like air or water to propagate. Electromagnetic waves have a wide range of applications in everyday life.

• Radio waves are used in broadcasting music and news on the radio.
• Microwaves are used to heat food quickly.
• Infrared waves are emitted by heaters and detected by night vision devices.
• Ultraviolet rays play a part in sanitizing equipment and producing vitamin D in our skin.

Each type of wave in the electromagnetic spectrum is characterized by a unique frequency and wavelength, determining its behavior and application.

Wavelength Comparison

When comparing electromagnetic waves, one essential factor to consider is wavelength. The wavelength is the distance between consecutive peaks of a wave. It is typically measured in meters or nanometers. In the electromagnetic spectrum, as wavelength decreases, frequency increases, which often changes how the wave interacts with matter.

• Longer wavelengths, like radio waves, are not easily absorbed by the atmosphere, allowing them to travel long distances.
• Shorter wavelengths, such as ultraviolet rays, have higher energy and can have more significant effects, like causing sunburns.

Understanding the order of wavelengths in the electromagnetic spectrum helps in determining which wave is suitable for specific uses or scientific studies. For example, knowing that ultraviolet rays have shorter wavelengths than visible waves or microwaves helps in identifying their ability to penetrate certain materials.

Ultraviolet Rays

Ultraviolet rays (UV rays) are a type of electromagnetic wave with wavelengths shorter than visible light but longer than X-rays. These rays are divided into three categories based on their wavelengths: UVA, UVB, and UVC.

• UVA rays have the longest wavelength in the ultraviolet spectrum and can penetrate the skin deeply, leading to aging signs like wrinkles.
• UVB rays have a slightly shorter wavelength and are more associated with sunburns and potential direct DNA damage.
• UVC rays have the shortest wavelength but are mostly absorbed by Earth's atmosphere and do not reach the surface.

While the ultraviolet part of the spectrum can be harmful, it is also tremendously useful. It is used in medical sterilization processes, air purification, and even in forensic sciences to detect substances invisible to the naked eye.