Question

1) Calculate the maximum wavelength of radiation (corresponding to the minimum energy) necessary to eject a 1s electron from a 27Al atom (which has a 1s1s binding energy of 1559.6 eVeV).

Answer 1

Solution:-

Binding Energy (E) = 1559.6 eV = (1559.6 × 1.602 × 10^-19) J

​​​​​​( 1eV = 1.602 × 10^-19 J)

Using the equation,

E = h

Where, h = Plank's constant (= 6.626 × 10^-34 J-s)

= frequency

We know that,   = c /

Where, c = speed of light (= 3 × 10⁸ m)

= wavelength.

Thus,

E = hc /

(1559.6 × 1.602 × 10^-19) = (6.626 × 10^-34 × 3 × 10⁸) /

or, = (6.626 × 10^-34 × 3 × 10⁸) / (1559.6 × 1.602 × 10^-19)

On solving, we get

= 7.956 × 10^-10 m = 7.956 Å

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