Answer:
Option B is correct.
4
Explanation:
We know that an atom consist of electron, protons and neutrons. Protons and neutrons are present with in nucleus while the electrons are present out side the nucleus.
All these three subatomic particles construct an atom. A neutral atom have equal number of proton and electron. In other words we can say that negative and positive charges are equal in magnitude and cancel the each other. For example, if neutral atom has 6 protons than it must have 6 electrons. The sum of neutrons and protons is the mass number of an atom while the number of protons are number of electrons is the atomic number of an atom.
In given problem we are given with 2 neutrons of helium. We know that the atomic number of He is 2. Thus Mass number of He is,
Number of neutrons + number of proton
2 + 2 = 4
Thus, option B is correct.
Answer:
Sea breeze moves from the areas of higher pressure on the water in the direction of the areas of lower pressure on land.
Explanation:
Sea breeze moves from the areas of higher pressure on the water in the direction of the areas of lower pressure on land. Whereas, land breeze blows from the areas of higher pressure on land to the areas of lower pressure on water.
Matter is everything and everything is made of matter, everything physical at least
The strumming is mechanical energy
the notes heard is sound energy
so use D
