When the excited electron of a H atom from $\mathrm{n}=5$ drops to the ground state, the maximum number of emission lines observed are _____

JEE Main · 2022 · 25 Jul 2022 · Shift 2 · Atomic Structure

When the excited electron of a H atom from

n = 5

drops to the ground state, the maximum number of emission lines observed are _____

Answer: 10

Solution

When an electron that has been raised to the level

n = 5

returns to the ground state, the atoms in the sample cascade down through every allowed intermediate level, so the spectrum contains a line for each transition between any two of the five levels

n = 1, 2, 3, 4, 5

. The number of such pairs of levels is

(2 5) = \frac{5 \times 4}{2} = 10

, so at most ten distinct emission lines are observed.

JEE Main · 2022 · 25 Jul 2022 · Shift 2 · Integer answer

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