MHT CET Chemistry Question (2026) — Solution

Step-by-step solution

The wave number v for a transition in a hydrogen atom is given by the Rydberg formula: v = R_H ( 1 n_1^2 - 1 n_2^2 ) For the Paschen series, the lower energy level is n_1 = 3. The lowest transition corresponds to the minimum energy difference, which occurs for the transition from the immediately higher energy level, n_2 = 4. Substituting these values into the formula: v = R_H ( 1 3^2 - 1 4^2 ) v = R_H ( 1 9 - 1 16 ) v = R_H ( 16 - 9 144 ) v = R_H ( 7 144 ) cm ^ -1 Answer: R_H ( 7 144 )\ cm ^ -1