Answer:
is the density of solid calcium.
Explanation:
Formula used :

where,
= density
Z = number of atom in unit cell
M = atomic mass
= Avogadro's number
a = edge length of unit cell
We have:
r = 197 pm = 



M = 40 g/mol
Z = 4
On substituting all the given values , we will get the value of 'a'.


is the density of solid calcium.
The vertical component of velocity is zero
Emissions are substances that are emitted; in an energy sense, these are most often waste products of a process aimed at obtaining useful work. The most common emissions from energy are associated with the generation of electricity and the transportation of people and goods.
<h3>How is energy emitted?</h3>
When the electron changes levels, it decreases energy and the atom emits photons. The photon is emitted with the electron moving from a higher energy level to a lower energy level. The energy of the photon is the exact energy that is lost by the electron moving to its lower energy level.
<h3>What is the energy of the emitted photons?</h3>
A photon can be emitted when an excited electron falls from a higher energy level to a lower level. The energy of the emitted photon will be equal to the energy drop. The energy of an electron and corresponding photon (emitted or absorbed) is expressed in electron- volts (eV's).
Learn more about emission here:
<h3>
brainly.com/question/2187993</h3><h3 /><h3>#SPJ4</h3>
coal is the most consumed