Hydrogen Spectrum and Balmer Series:
- The spectral lines in the Balmer series correspond to electronic transitions from higher energy levels to \( n = 2 \).
- As the wavelength decreases (moving towards the ultraviolet region), the lines become more closely spaced due to decreasing energy gaps.
- The intensity of the lines also decreases due to lower transition probabilities.
Thus, the correct answer is Closer together and weaker in intensity.