Question

The wavelength of radiation required to remove the electron of hydrogen atom (lonisation energy
21.7 x 10 erg) from n 2 orbit to n = infinity
1) 3.664 x 10 cm
3.66 x 10 cm
3) 3.66 x 10 cm
4) 3.664 x 10 cm​

Answer 1

Answer:

3.67 * 10⁻⁵ cm

Explanation:

To calculate the energy required to remove electron from atom, n = ∞ is to be taken.

Energy of an electron in nth orbit of hydrogen is given by

E = 21.7 * 10⁻¹² * 1/n² ergs

∴ ∆E = 21.7 * 10⁻¹² (1/2² – 1/∞²)

= - 21.7 * 10⁻¹² (1/4 – 0) = 21.7 * 10⁻¹² * 1/4

= - 5.42 * 10⁻¹² ergs

∴ ∆E = hc/λ (∵ v = c/λ)

Or λ = hc/∆E

Substituting the values, λ = 6.627 *10⁻²⁷ *3 *1010/5.42 * 10⁻¹²

= 3.67 * 10⁻⁵ cm

Answer 2

Answer:

3.67*10^-5

Explanation:

To calculate the energy required to remove electron from atom, n = ∞ is to be taken.

Energy of an electron in nth orbit of hydrogen is given by

E = 21.7 * 10⁻¹² * 1/n² ergs

∴ ∆E = 21.7 * 10⁻¹² (1/2² – 1/∞²)

= - 21.7 * 10⁻¹² (1/4 – 0) = 21.7 * 10⁻¹² * 1/4

= - 5.42 * 10⁻¹² ergs

∴ ∆E = hc/λ (∵ v = c/λ)

Or λ = hc/∆E

Substituting the values, λ = 6.627 *10⁻²⁷ *3 *1010/5.42 * 10⁻¹²

= 3.67 * 10⁻⁵ cm