According to Boyle's law, at constant temperature, the pressure of a gas is inversely proportional to its: MCQ with Answer and Explanation

Explanation:
Bohr's model successfully explains the spectrum of hydrogen and hydrogen-like species (single electron systems like He⁺, Li²⁺). However, it fails to explain the spectra of multi-electron atoms due to electron-electron repulsions and cannot account for the splitting of spectral lines in magnetic (Zeeman) and electric (Stark) fields.

Explanation:
Rhizobium bacteria form root nodules in leguminous plants (peas, beans, clover) and fix atmospheric N₂ into ammonia, providing nitrogen to the plant, while the plant supplies carbohydrates. Azotobacter and Azospirillum are free-living nitrogen fixers. Pseudomonas is a general soil bacterium. Symbiotic association is mutualistic. Inoculating seeds with Rhizobium culture increases soil fertility.

Explanation:
J.J. Thomson discovered the electron in 1897 through his experiments with cathode ray tubes. He demonstrated that cathode rays were composed of previously unknown negatively charged particles, which were later named electrons. This discovery proved that atoms were not indivisible and led to his 'plum pudding' model.