Problem 2183 - JEE Physics

Question

In electromagnetic spectrum, the visible light lie between (A) radiowaves and microwaves (B) ultraviolet rays and infrared rays (C) ultraviolet rays and \(\mathrm{x}\) rays (D) infrared rays and microwaves

Step-by-Step Solution

Answer

In the electromagnetic spectrum, visible light lies between infrared rays (longer wavelengths) and ultraviolet rays (shorter wavelengths). Therefore, the correct answer is (B) Ultraviolet rays and infrared rays.

Step 1: List the components of the electromagnetic spectrum in order

Here's the general order of the electromagnetic spectrum, from the longest wavelength to the shortest wavelength: 1. Radiowaves 2. Microwaves 3. Infrared rays 4. Visible light 5. Ultraviolet rays 6. X-rays 7. Gamma rays

Step 2: Examine each choice

Now, let’s examine each of the choices and see which one correctly places visible light between two other types of electromagnetic radiation: (A) Radiowaves and microwaves: Visible light lies between infrared rays and ultraviolet rays, not between radiowaves and microwaves. (B) Ultraviolet rays and infrared rays: This choice correctly places visible light between infrared rays and ultraviolet rays. (C) Ultraviolet rays and X-rays: Visible light lies between infrared rays and ultraviolet rays, not between ultraviolet rays and X-rays. (D) Infrared rays and microwaves: Visible light lies between infrared rays and ultraviolet rays, not between infrared rays and microwaves.

Step 3: Choose the correct answer

Based on our analysis, the correct answer is: (B) Ultraviolet rays and infrared rays. Visible light lies between infrared rays (longer wavelengths) and ultraviolet rays (shorter wavelengths) in the electromagnetic spectrum.

Key Concepts

Visible Light

Visible light is the portion of the electromagnetic spectrum that is visible to the human eye. It consists of wavelengths that range from approximately 400 nanometers (nm) to 700 nm. This means that it sits right in the middle of the electromagnetic spectrum between ultraviolet (UV) rays and infrared (IR) rays. Our eyes perceive this range of electromagnetic waves as different colors of light, creating the beautiful array of colors from violet to red.

• Violet: Around 400 nm
• Blue
• Green
• Yellow
• Orange
• Red: Around 700 nm

Colors are simply our brain's interpretation of different wavelengths. For example, shorter wavelengths within the visible light range appear blue or violet, while longer wavelengths appear red.

Ultraviolet Rays

Ultraviolet rays, often abbreviated as UV rays, are electromagnetic waves with wavelengths shorter than visible light and longer than X-rays. These wavelengths range from about 10 nm to 400 nm, placing them just above visible light in the electromagnetic spectrum. Because they have a higher energy level than visible light, they are able to penetrate deeper into substances.

• UV rays are responsible for causing sunburns, as they can damage your skin's cells.
• There are different types of UV rays, such as UVA, UVB, and UVC, each with varying degrees of energy and effects.
• UVC is the highest energy type of UV ray, but it is largely absorbed by the earth's atmosphere.

It's important to protect yourself from UV rays, as prolonged exposure can increase the risk of skin cancer and other health issues.

Infrared Rays

Infrared rays are a type of electromagnetic radiation with wavelengths longer than those of visible light but shorter than microwaves. They typically range from 700 nm to 1 millimeter (mm), making them the type of radiation just below visible light in the electromagnetic spectrum. Infrared rays are experienced as heat, and they are commonly used in various technologies.

• They play an important role in thermal imaging cameras, which can detect temperature differences.
• Remote controls often use infrared signals to communicate with electronic devices.
• Infrared radiation is also used in night vision equipment.

Infrared rays are not visible to the human eye, but we can feel them as warmth. This is why we can feel the sun's heat even if we can't see the infrared rays it emits.