The correct answer is: A. February 23
National Science Day is celebrated in India on February 23 every year to commemorate the discovery of the Raman Effect by Indian physicist Sir Chandrasekhara Venkata Raman on February 28, 1928. The Raman Effect is the scattering of light by a substance, and the change in the wavelength of the scattered light is called Raman scattering. Raman was awarded the Nobel Prize in Physics in 1930 for his discovery.
The Raman Effect is a very important phenomenon in physics and chemistry, and it has many applications in a variety of fields, including spectroscopy, materials science, and biology. It is also used in Raman imaging, which is a non-destructive technique for studying the structure and composition of materials.
National Science Day is a day to celebrate the achievements of Indian scientists and to promote science and technology in India. It is also a day to encourage young people to take up careers in science and technology.
Here is a brief explanation of each option:
- Option A: February 23 is the correct answer.
- Option B: February 25 is not the correct answer because it is not the day on which National Science Day is celebrated in India.
- Option C: February 26 is not the correct answer because it is not the day on which National Science Day is celebrated in India.
- Option D: February 28 is not the correct answer because it is the day on which Sir Chandrasekhara Venkata Raman discovered the Raman Effect, but it is not the day on which National Science Day is celebrated in India.