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Hydrogen atom is excited from ground state to another state with principal quantum number equal to 4. Then the number of spectral lines in the emission spectra will be:

1. 2
2. 3
3. 5
4. 6

Correct answer: 6

Solution

From an excited state n = 4 down to ground, the number of distinct spectral lines is n(n-1)/2 = 4*3/2 = 6.

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