Question

We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used ______.

Options

• 5 KeV

• 8 KeV

• 10 KeV

• 12 KeV

Answer 1

We wish to observe an object which is 2.5Å in size. The minimum energy photon that can be used is 5 KeV.

Explanation:

The wavelength of the waves must be of the same order of magnitude or smaller than the size of the object being viewed for scattering to occur. As a result, the maximum possible wavelength in the current issue is λ_max = 2.5 Å.

Hence minimum energy is,

`E_{min} = hv_min = (hc)/max`

= `(12.40 xx 10^3)/(2.5Å)` eV.Å

= 4.96 × 10³ eV

= 5 KeV