Atomic Spectra

Step 1: Use the formula for frequency of transition in hydrogen atom: Step 2: Paschen series has transitions ending at .
- First Paschen line:
- Second Paschen line:
Step 3: Calculate the frequencies. Step 4: Frequency difference: Find LCM of 144 and 225 = 3600, so: We take magnitude (positive value): Step 5: Select the correct option.
The frequency difference is , which matches option (3).