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:
Two lines will be extra for the first and last wavelength.
∴ Total number of lines = 36 + 2 = 38