Answer:
B
Explanation:
machanical waves like sea waves need a medium.
but electromagnetic waves never need a medium
but can also travel through medium
Answer:
The lines fall somewhere in one or more of the colors in the spectroscope. When electrons in an atom are excited by shooting electricity through them for instance, some electrons are forced to temporatily jump to a higher energy level. As it is only temporary, the electron soon falls back down to its own level. However as it loses potential energy it gives off a brief burst of light energy which we can see. If the light is red then the electron didn't jump very high, and therefore lost only a little eneergy falling back down. If the light is violet or purple it fell from a high orbital and released a lot of energy falling back down. Everything else falls in between.
Explanation:
The radiation emitted is a beta particle with a -1 charge. Beta particles have a <span>medium penetrating power. An emission of beta particles requires shielding because of the hazards it pose to humans. Thus, one characteristic of this radiation is that <span>some shielding is required.</span></span>
The molecular mass of 
is:
2·1 + 1·32 + 4·16 = 98 g/mol
The amount of solute, expressed by mol, is:
The molar concentration definition is: 
Doing the calculations:
(If you detect any mistakes in my English report me them, please).
