JEE Advanced levelOne or more correct optionsDifficulty 3 of 3as107
Use RH=1.097×107m−1 and E1=−13.6eV. Select the correct statements about the series limits of hydrogen.
AThe Paschen limit corresponds to a photon energy of 1.89eV
BThe Lyman limit lies near 91nm
CThe wavelengths of the Lyman, Balmer and Paschen limits are in the ratio 1:4:9
DThe Balmer limit corresponds to a photon energy of 3.4eV
Answer: B, C, D
The limit is 1/λ=RH/nf2, so λ∝nf2=1:4:9. Energies are 13.6/nf2: 3.4eV for Balmer and 1.51eV for Paschen (1.89 eV is the H-alpha line). The Lyman limit is 1/RH=91.2nm.