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Heat treatment of muscular pain involves radiation of wavelength of about 900 nm. Which spectral line of H atom is suitable for this? Given: Rydberg constant R_H = 10^5 cm^-1, h = 6.6 × 10^-34 J s, c = 3 × 10^8 m/s (1) Paschen series, ∞ → 3 (2) Lyman series, ∞ → 1 (3) Balmer series, ∞ → 2 (4) Paschen series, 5 → 3
- Paschen series, ∞ → 3
- Lyman series, ∞ → 1
- Balmer series, ∞ → 2
- Paschen series, 5 → 3
Correct answer: Paschen series, ∞ → 3
Solution
The Paschen series corresponds to transitions where electrons fall to the third energy level (n=3) from higher levels, emitting infrared radiation with wavelengths around 900 nm, making it suitable for heat treatment of muscular pain.
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