see
below
Explanation:
refractive index = speed of light in vacuum / speed of light in medium
light travels at a speed of 3.0 x 10^8 m/s in vacuum
refractive index = 3.0 x 10^8 / 2.0 x 10^8
refractive index = 1.5
hope this helps, please mark it
Answer: When a material is heated or cooled, two changes may happen to the particles within the material: Chemical bonds between the particles may form, break or stretch. There is a change in the chemical potential store of energy in the material. The material will heat up or cool down as the particles within it gain or lose speed.
Explanation:
Answer:

Explanation:
As we know that the level of intensity is given as

here we know



now the sound is travelling in all possible directions so we have



now for level of sound we have


B. all of nature follows uniform, unchaining laws.
Answer: a. To control all of the people in the community
Explanation:
The sport organization help in bring people of different communities together. It removes any kind of discrimination based on caste, gender, race, and others. People are united in a single team to bring about unity in them. The sport organization does not control the people in the community instead can bring change in their thinking and opinion about people of the other community. The sports activities are recreational in nature, they build social interaction between people of different communities, control good health, make communities safer.