Answer:
D
Explanation:
he describes as he writes them down
When riding a bicycle, if you stop pedaling you will still continue to move forward due to inerita.
First one, for instance they become conductors or insulators depending on the temperature!
Explanation :
When an electron jumps from one energy level to another, the energy of atom gets changed.
If a photon gets absorbed, the electron will move to higher energy levels and then fall back to the lower energy levels. Then each time a photon will be absorbed whose energy is given by difference between the initial and final energy levels i.e
In Balmer series, the transition is from higher energy levels to n = 2.
So, the necessary condition for Balmer series is that the electron should be at first excited state or n = 2 level as shown in figure.