Practice question

Given: What is the maximum number of emission lines when an electron drops from n = 5 to the ground state in a hydrogen atom? These values define the system as per NCERT data. Formula: Number of emission lines = n(n-1)/2, where n = 5. This is the standard NCERT relation for this phenomenon. Substitution & Calculation: So, 5 × 4/2 = 10. Result: The computed value matches the expected outcome and confirms the correct choice. Units and powers like J kg⁻¹ K⁻¹, m/s², 10⁻⁵ are properly used as per NCERT.