The answer is D. Effective collisions lead to chemical reactions!
<span>Energy is absorbed and then released to form an emission line.
When electrons absorb energy they increase there energy level. This is only temporary and the excited electron then relaxes back down to its original energy level releasing energy.
The energy is released in form of EM radiation of a specific frequency depending on the element and how many energy levels the electron relaxes.
This forms an emission line.</span><span />
<h2>Answer : Option C) Smaller volume - crowded particles - more collisions - high pressure</h2><h3>Explanation : </h3>
The kinetic molecular theory of gases explains that if there is small volume of gas there will be more crowding of the gas molecules inside the container. The crowded gas molecules will collide with each other and also with the walls of container as a result, exchange of energies will take place. Which will increase the pressure inside the container, and will raise the pressure than the initial pressure.