Question

The Balmer series for the $H$-atom can be observed

• A. in any transition in a $H$-atom.
  
• B. if we measure the frequencies of light emitted when an excited atom falls to the ground state.
  
• C. if we measure the frequencies of light emitted due to transitions between excited states and the first excited state.
  
• D. ​​​​​as a sequence of frequencies with the higher frequencies getting closely packed.

Answer 1

Answer: (C), (D)

​​​​​as a sequence of frequencies with the higher frequencies getting closely packed.

According to $H$-atom spectrum, when electron jumps from higher energy $(n=3,4,5\dots )$ state to energy state $(n=2)$, the spectrum of light is called Balmer series. It comes into the visible region, which has maximum wavelength $=\frac{36}{5R}$ and minimum wavelength$=\frac{4}{R}$.

Also we know that spectrum lines become closer if electron jumps from higher energy state to ground state.

$\text{Final Answer}:$ (b), (d)