Which one of the following is a type of Electro-magnetic radiation?
**Core Concept**
Electro-magnetic radiation is a form of energy that includes various types of waves, such as radio waves, microwaves, infrared, visible light, ultraviolet, X-rays, and gamma rays. These waves are characterized by their frequency and wavelength, and they can be classified based on their energy and application in medicine.
**Why the Correct Answer is Right**
Visible light is a specific type of electromagnetic radiation that is visible to the human eye. It has a frequency range of approximately 4 x 10^14 to 8 x 10^14 Hz and a wavelength range of approximately 400-700 nanometers. Visible light is essential for vision, and it is also used in various medical applications, such as phototherapy and laser surgery.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because radio waves are a type of electromagnetic radiation, but they are not visible to the human eye. They have a much longer wavelength and lower frequency than visible light.
**Option B:** This option is incorrect because microwaves are also a type of electromagnetic radiation, but they are not visible to the human eye. They have a specific frequency range and are used in cooking and medical applications, but they are not a type of visible light.
**Option C:** This option is incorrect because infrared radiation is a type of electromagnetic radiation, but it is not visible to the human eye. It has a longer wavelength and lower frequency than visible light and is often felt as heat.
**Option D:** This option is incorrect because ultraviolet radiation is a type of electromagnetic radiation, but it is not visible to the human eye. It has a shorter wavelength and higher frequency than visible light and is often associated with skin damage and cancer.
**Clinical Pearl / High-Yield Fact**
Visible light is an essential component of human vision, and its interaction with the retina is critical for the perception of color and vision. The human eye is most sensitive to light in the green-yellow spectrum, which is why green and yellow colors are often used in medical settings to provide high contrast and visibility.
**Correct Answer:** C.