# A Spectroscopic Instrument Can Resolve Two Nearby Wavelengths λ and λ + δλ If λ/δλ is Smaller than 8000. this is Used to Study the Spectral Lines of the Balmer Series of - Physics

Short Note

A spectroscopic instrument can resolve two nearby wavelengths λ and λ + Δλ if λ/Δλ is smaller than 8000. This is used to study the spectral lines of the Balmer series of hydrogen. Approximately how many lines will be resolved by the instrument?

#### Solution

The range of wavelength falling in Balmer series is between 656.3 nm and 365 nm.

It is given that the resolution of the instrument is λ/ (λ + ∆λ) < 8000.

Number of wavelengths in this range will be calculated in the following way:

(656.3-365)/8000 = 36

Two lines will be extra for the first and last wavelength.

∴ Total number of lines = 36 + 2 = 38

Concept: Hydrogen Spectrum
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#### APPEARS IN

HC Verma Class 11, Class 12 Concepts of Physics Vol. 2
Chapter 21 Bohr’s Model and Physics of Atom
Q 19 | Page 384