Question

When an excited hydrogen atom returned to its ground state, some visible quanta were observed along with other quanta. Which of the following transitions must have occured?

• A. $2\to 1$
• B. $3\to 1$
• C. $4\to 1$
• D. $5\to 1$

Answer 1

Answer: (A)

$2\to 1$

The transition $2\to 1$ must have occurred.
This is because the visible quanta are observed in the Balmer series when the electron de-excites by the transition from higher level to the second level. Once the electron reaches the second level, it will de-excite to ground state which will result in the transition $2\to 1$. The quanta emitted will now be in UV region.