1

IIT-JEE 1995

Subjective
Iodine molecule dissociates into atoms after absorbing light of 4500 Å. If one quantum of radiation is absorbed by each molecule, calculate the kinetic energy of iodine atoms. (Bond energy of I2 = 240 kJ mol-1)

2.165 $\times$ 10-20
2

IIT-JEE 1993

Subjective
What transition in the hydrogen spectrum would have the same wavelength as the Balmer transition n = 4 to n = 2 of He+ spectrum?

n = 2 to n = 1
3

IIT-JEE 1993

Subjective
Estimate the difference in energy between 1st and 2nd Bohr orbit for a hydrogen atom. At what minimum atomic number, a transition from n = 2 to n = 1 energy level would result in the emission of X-rays with $\lambda = 3.0 \times {10^{ - 8}}$? Which hydrogen atom like species does this atomic number correspond to?

10.22 eV, 2, He+
4

IIT-JEE 1990

Subjective
According to Bohr's theory, the electronic energy of hydrogen atom in the nth Bohr's orbit is given by ${E_n} = {{ - 21.6 \times {{10}^{ - 19}}} \over {{n^2}}}J$. Calculate the longest wavelength of light that will be needed to remove an electron from the third Bohr orbit of the He+ ion.

2055 Å