Question

10. A single slit 1.0 mm wide is illuminated by 450 nm light. What is the central maximum (in cm) width in the diffraction pattern on a screen 5.0 m away?

A. 3 cm

B. 0.8 cm

C. 0.45 cm

D. 0.5 cm

Answer 1

A single slit 1.0 mm wide is illuminated by 450 nm light. What is the central maximum (in cm) width in the diffraction pattern on a screen 5.0 m away?

$$(m+1/2)\lambda=d\sin\theta,\\\space\\ \theta=0.0129°.$$

The width:

$$x=2L\tan\theta=2.25\text{ mm}.$$

Two such fringes give 0.45 cm.