Which of the following is NOT a source of release of smokestacks?
-
A.
Smelters
-
B.
Industries
-
C.
Thermal power plants
-
D.
Rivers
Correct Answer:
D. Rivers
Explanation:
A refractive index less than one indicates that the phase velocity of light within that specific medium is greater than the speed of light in a vacuum. While the theory of relativity prevents information or matter from exceeding the speed of light (c), the phase velocity—which represents the speed of the wave's crests rather than the signal itself—can surpass this limit in certain conditions. This phenomenon typically occurs in environments like the Earth's ionosphere, in plasma, or with specific radiation types such as X-rays, often causing the waves to bend away from the normal or reflect back.
Click below to open Discussion & Feedback
0 Issues
Please
login to comment or Report Issues.