Which form of the law of conservation of energy describes the motion of the block when it slides from the top of the table to the bottom of the ramp?
the frozen balloon shrank because the average kinetic energy of the gas molecules in a balloon decreases when the temperature decreases. this makes the molecules move more slowly and have less frequent and weaker collisions with the inside wall of the balloon, which causes the balloon to shrink a little.
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.