Answer:
Level 4 to level 2
Explanation:
Electrons in an atom are contained in specific energy levels (1, 2, 3, and so on) having different distances from the nucleus. When light is emitted by electrons from one energy level to a lower level, level 4 to level 2 has the greatest energy.
Hence, the correct option is "Level 4 to level 2".
Answer:
D. The period would decrease by sqrt (2)
Explanation:
The period of a mass-spring system is given by:

where
m is the mass
k is the spring constant of the spring
If the spring constant is doubled,
k' = 2k
So the new period will be

So the correct answer is
D. The period would decrease by sqrt (2)
Answer:
what r the options that are there
Explanation:
The correct answer is the Black Market.
The Black Market refers to the informal (and sometimes formal) system of trading of illegal goods by merchants and dealers of products such a weapons, drugs, and good that have been banned by countries. This can also apply to informal marketplaces in countries with sanctions placed upon them get goods that formal treaties are blocking the people from accessing.