Although we have discussed single-slit diffraction only for a slit, a similar result holds when light bends around a straight, thin object, such as a strand of hair. In that case, is the width of the strand. From actual laboratory measurements on a human hair, it was found that when a beam of light of wavelength 632.8 nm was shone on a single strand of hair, and the diffracted light was viewed on a screen 1.25 m away, the first dark fringes on either side of the central bright spot were 5.22 cm apart.

How thick was this strand of hair???
a= Mm?

Width of hair is "1.96 10⁻⁵ m"

Explanation:

For this diffraction problem they tell us that it is equivalent to the diffraction of a single slit, which is explained by the equation      a sin θ =±  m λWhere the different temrs are: “a” the width of the hair, λ the wavelength, θ the angle from the center, m the order of diffraction, which is the number of bright rings (constructive diffraction)  We can see that the diffraction angle is missing, but we can find it by trigonometry, where L is the distance of the strand of hair to the observation screen and "y" is the perpendicular distance to the first minimum of intensity      L = 1.25 m 100 cm/1m   = 125 cm      y = 5.06 cm       Tan θ = y/L     Tan θ = 5.06/12      θ = tan⁻¹ ( 0.0405)      θ =  2.32ºWith this data we can continue analyzing the problem, they indicate that they measure the distance to the first dark strip, thus m = 1     a = m λ / sin θ     a = 1 633 10⁻⁹ 1.25/sin 2.3     a = 1.96 10⁻⁵ m       a = 0.0196 mmHence, "the width of the strand of hair is   1.96 10⁻⁵ m" is correct answer

It is important for meteorologists because precipitation can affect how low or high the temperature is and this can affect how accurate the information that he/she is providing you with. For example, lets say it is/was really hot outside but then it starts raining outside. You may notice that the temperature goes down because of the rain. (let me know if you need me to explain more)

Hope this helps!!

Have a nice day and stay safe :)

Explanation: