Answer: If a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
Explanation:
The relation between energy and wavelength is as follows.
This means that energy is inversely proportional to wavelength.
As it is given that energy of a hydrogen atom and a helium atom is same.
Let us assume that 
. Hence, relation between their wavelengths will be calculated as follows.
... (1)
... (2)
Equating the equations (1) and (2) as follows.
Thus, we can conclude that if a hydrogen atom and a helium atom have the same kinetic energy then the wavelength of the hydrogen atom will be roughly equal to the wavelength of the helium atom.
Answer: Option (b) is the correct answer.
Explanation:
It is known that metals are the species which readily lose an electron and tend to attain a positive charge.
For example, atomic number of sodium is 11 and its is an alkali metal. It electronic distribution is 2, 8, 1.
And, in order to attain stability it readily loses an electron and thus it become 
ion.
Also, it is known that species which tend to transfer or donate their valence electrons to other atoms tend to form ionic bond and the compound formed is known as ionic compound.
Therefore, we can conclude that the statement metal atoms held together by ionic bonds best describes a metal solid.
The penetrating power of alpha rays, beta rays, and gamma rays varies greatly. Alpha particles can be blocked by a few pieces of paper. Beta particles pass through paper but are stopped by aluminum foil. Gamma rays are the most difficult to stop and require concrete, lead, or other heavy shielding to block them.
<span>Kind of substance besides water:
The best example of hydrogen bonding excluding water is DNA. The two strands of polymers are connected by hydrogen bonds between the nucleotide bases</span>.
Answer:
<h3>A-5N B-6N C-7N D-8N</h3>
Explanation:
i hope it helps ;)
