Electromagnetic Spectrum

Step 1: Understanding the Concept:
The visible spectrum is the portion of the electromagnetic spectrum that is visible to the human eye. It consists of a range of colors, each corresponding to a different wavelength of light. The question asks to identify the color with the largest wavelength.
Step 2: Detailed Explanation:
The colors of the visible spectrum are typically remembered by the acronym VIBGYOR, which stands for Violet, Indigo, Blue, Green, Yellow, Orange, and Red.
This sequence is arranged in order of increasing wavelength (or decreasing frequency and energy).
- Violet has the shortest wavelength (around 400 nm).
- Red has the longest wavelength (around 650-700 nm).
Therefore, among the given options, Red has the largest wavelength.
Step 3: Final Answer:
In the visible spectrum, Red has the largest wavelength. So, option (A) is correct.

Step 1: Understanding the Concept:
The electromagnetic (EM) spectrum is the range of all types of EM radiation. Radiation is classified by wavelength, frequency, or energy. Wavelength ( ) and frequency ( ) are inversely related ( ), and energy ( ) is directly proportional to frequency ( ). Therefore, minimum wavelength corresponds to maximum frequency and maximum energy.
Step 2: Detailed Explanation:
Let's arrange the given electromagnetic radiations in order of decreasing wavelength (or increasing frequency/energy):
1. Microwaves: Wavelengths range from about 1 meter to 1 millimeter. They have longer wavelengths and lower energy than the other options.
2. Ultraviolet (UV): Wavelengths are shorter than visible light, typically from 400 nm to 10 nm.
3. X-rays: Wavelengths are shorter than UV rays, typically from 10 nm to 0.01 nm.
4. γ-rays (Gamma rays): They have the shortest wavelengths in the entire electromagnetic spectrum, typically less than 0.01 nm (or 10 picometers). They are the most energetic form of electromagnetic radiation.
The order from longest to shortest wavelength is: Microwaves>Ultraviolet>X-rays>γ-rays.
Step 3: Final Answer:
Among the given options, γ-rays have the minimum wavelength. Therefore, option (D) is correct.