Coherent monochromatic light is incident on a slit whose width is 0.0211 mm. The
ID: 1390308 • Letter: C
Question
Coherent monochromatic light is incident on a slit whose width is 0.0211 mm. The diffraction pattern is viewed on a screen that is placed 3.17 m from the slit. The distance along the screen from the middle of the central maximum to the first dark fringe is 10.1 cm. What is the wavelength of the light? (answer in meters please) Coherent monochromatic light is incident on a slit whose width is 0.0211 mm. The diffraction pattern is viewed on a screen that is placed 3.17 m from the slit. The distance along the screen from the middle of the central maximum to the first dark fringe is 10.1 cm. What is the wavelength of the light? (answer in meters please)Explanation / Answer
D=3.17m
x=10.1 cm
the condition to get minimum intesity in diffraction pattern is,
d*sin(theta)=(2n+1)*lambda/2
d*(x/D)=lambda/2 (for fist dark fringe)
lambda=2x*(d/D)
=2*(10.1*10^-2)*(0.0211*10^-3/3.17)
=0.13445*10^-5 m
=1344.5*10^-9 m
=1344.5 nm