Question

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?

Answer 1

Given:

• A spectroscopic instrument can resolve two nearby wavelengths λ and λ + Δλ if λ/Δλ is smaller than 8000.

To find:

• Number of lines will be resolved by the instrument.

Answer:

• The range of Balmer series is 656.3 nm to 365 nm.

• Number of lines in this above range =$\frac{656.3-365}{8000} = 36$

• Number of lines will be resolved by the instrument = 36 + 2 = 38

        2 is added for the lines representing first and last wavelength.][