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The ratio of momentum of the photons of the 1st and 2nd line of Balmer series of hydrogen atoms is α/β. The possible values of α and β are:

Asked in JEE Main 6th April 1st Shift 2026 · Spectral series and wavelengths

(1) 27 and 20
(2) 3 and 16
(3) 5 and 36
(4) 20 and 27

Answer: (4) 20 and 27

Step-by-step solution

p=h/λ∝1/λ.

First line 3→2: 1/(λ₁)=R(1/4-1/9)=(5R)/(36).

Second line 4→2: 1/(λ₂)=(3R)/(16).

(p₁)/(p₂)=(5/36)/(3/16)=(20)/(27)

Why the other options are wrong

(1) Inverts the ratio by taking p∝λ.
(2) Uses only the bracket of the second line.
(3) Uses only the bracket of the first line.

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