Energy of an electron is given by E = - 2 . 1 7 8 × 1 0 - 1 8 Z 2 n 2 J . Wavelength of light required to excite an electron in a hydrogen atom from level n=1 to n=2 will be : h = 6.62 × 10 - 34 J s a n d c = 3.0 × 10 8 m s - 1

Step-by-step solution

E 1 = − 2 .178 × 10 − 18 × 1 1 = − 2 .178 × 10 − 18 J = 2 .178 × 10 − 18 1 .6 × 10 − 19 = 13 .6   eV E 2 = − 2 .178 × 10 − 8 ( 2 ) 2 = − 2 .178 × 10 − 18 4 = 0 .5448 × 10 − 18 J = − 3 .4   eV Δ E = E 2 - E 1 = - 3 . 4 - - 13 . 6 = 10 . 2   eV λ   in   Å = 12400 10 .2 ≈ 1214   Å = 1214 × 10 − 10 m = 1 .214 × 10 − 7 m ∴ 1 &#