Question

The radius of the half period zone is proportional to __________

(a) The wavelength of light

(b) The square root of the frequency of light

(c) The square root of the wavelength light

(d) The frequency of light

I had been asked this question in semester exam.

Enquiry is from Fresnel and Fraunhofer Diffraction in portion Diffraction of Engineering Physics II

Answer 1

Correct answer is (c) The square root of the wavelength light

For explanation I would say: We know that the formula for the radius of half period zone = \(\sqrt{nb\lambda}\), where n is a natural number. Thus, it is proportional to the square root of wavelength light and inversely proportional to the square root of the frequency of light.