Red light of wavelenght 633nm from a helium-neon laser passesthrough a slit 0.350 mm wide. the diffraction patteren is obserevedon a screen 3.00 m away. what is the width of the first brightfringe on either side of the centeral one? this is question from book. i already read the solutiony=D(2-1). i do not underestand how they got thisequation. can you please help me? thanks. Red light of wavelenght 633nm from a helium-neon laser passesthrough a slit 0.350 mm wide. the diffraction patteren is obserevedon a screen 3.00 m away. what is the width of the first brightfringe on either side of the centeral one? this is question from book. i already read the solutiony=D(2-1). i do not underestand how they got thisequation. can you please help me? thanks.
Explanation / Answer
wavelength = 633 nm = 633 * 10 ^ -9 m slit width d = 0.35 mm = 0.35 * 10 ^ -3 m distance of the screen from slit D = 3 m condition for 1 st minimum is d sin = at small angles sin ~ tan = y / D from this d ( y / D ) = So, y = D / d So, width of the first bright fringe on either side of centralone = 2 y =10.8514 * 10 ^ -3 m