The distance between the first and fifth minima of a singleslit diffraction pattern is 0.35 mm with the screen 40 cm away from the slit, when light of wavelength 550 nm is used. (a) Find the slit width. (b) Calculate the angle u of the first diffraction minimum.

632.8 nm) is used to calibrate a diffraction grating. If the first-order maximum occurs at 21.0°, what is the spacing between adjacent grooves in the grating? (In this problem, assume that the light is incident normally on the grating.) μm A helium-neon laser (1 =

Light of wavelength 588.2 nm illuminates a slit of width 0.63 mm. (a) At what distance from the slit should a screen be placed if the first minimum in the diffraction pattern is to be 0.86 mm from the central maximum? (b) Calculate the width of the central maximum. Step 1 (a) As shown in the figure, dark bands or minima occur where sin 0 = m(2/a). For the first minimum, m = 1 and the distance from the center of the central maximum to the first minimum is y₁ = L tan 8, where L is the distance of the viewing screen from the slit. 32 sin dark = 22/a 31 sin dark = λ/a HE 0 -1 sin dark = -λ/a -2 sin dark = -22/a Viewing screen a Because is very small, we can use the approximation tan sin 0 = m(2/a). Substituting the approximation and solving for the distance to the screen, we have 6.3 x 10 m ³ m ) (₁ L = = y ₁ ( ² ) = x 10-3 m x 10-⁹ m m.

A parallel beam of light of wavelength 500 nm falls on a narrow slit and the resulting diffraction pattern is observed on a screen 1 m away. It is observed that the first minimum is at a distance of 2.5 mm from the centre of the screen. Find the width of the slit.