Diffraction

Diffraction – Path difference

• Notice that these 2 waves are OUT OF PHASE. When they hit they screen they both hit at the different relative positions, one at the bottom of a crest and the other coming out of a trough. Thus their amplitudes SUBTRACT.
• E'tibor bering, bu 2 ta to'lqin FAZADAN CHAQADI. Ular ekranga urilganda, ikkalasi ham har xil nisbiy pozitsiyalarga toqnashadi, biri tepalikning pastki qismiga, ikkinchisi esa yuqoriga chiqadi. Shunday qilib, ularning amplitudalari AYRILADI.
• How much farther did the red wave have to travel?
• Qizil to'lqin qancha masofani bosib o'tishi kerak edi?
• Exactly – ONE HALF OF A WAVELENGTH
• Aynan - to'lqin uzunligining bir yarimi

• 

• The call this extra distance the PATH DIFFERENCE. The path difference and the ORDER of a fringe help to form another pattern.
• Ushbu qo'shimcha masofani YO'LLAR FARQI deb nomlang. Yo'l farqi va chekka TARTIBI boshqa naqsh hosil qilishga yordam beradi.

Diffraction – Path Difference

• 0.5

• 0.5

• 1.5

• 1.5

• The dark fringes you see on either side of the central maximum are multiple wavelengths from the bright central. And it just so happens that the multiple is the ORDER.
• Siz markaziy maksimalning har ikki tomonida ko'rgan qorong'u chiziqlar yorqin markazdan bir nechta to'lqin uzunliklari. Va shunday bo'ladiki, ko'plik TARTIB bo'ladi.

• Therefore, the PATH DIFFERENCE is equal to the ORDER plus a HALF, times A WAVELENGTH
• Shuning uchun, YO'L FAQI TARTIBI plyus YARIMI, A TO'LQIN UZINLIK ga teng.

• P.D. = (m+1/2)
• Destructive)

Path Difference - Summary

• For CONSTRUCTIVE INTERFERENCE or MAXIMUMS use:
• For DESTRUCTIVE INTERFERENCE or MINIMUMS use:

• P.D. = m

• P.D. = (m+1/2)

• Where “m”, is the ORDER. Refer to slides 6 and 11.