Answer to Question #283522 in Physics for Ella

Question

7. Which of the following accurately defines diffraction?

A. Where waves like light or sound spread out as they move around an object or

through a slit

B. Where waves like light or sound bunch together as they move around an object

or through a slit.

C. Where waves like light of sound move through an object or sit unaffected

d. Where waves liko light or sound spread out as they move through a silt, but NOT around an object

8. When does single-slit diffraction occur?

A. when the slit width is smaller than the wavelength

B. when the slit width is the same as the wavelength

C. when the slit width is slightly larger than wavelength

D. both a and b

9. A single narrow slit is illuminated with red light of wavelength 632.8 nm. A screen placed 1.60 m from the slit shows a typical singe-slit diffraction pattern. The separation between the two first minima is 4.0 mm. What is the width of the slit?

A. 0.25 mm

B. 0.51 mm

C. 2.5 mm

D. 5.1 mm

Answer 1

7. B

8. D

9. The width of the slit is

$$d=\dfrac{m\lambda L}{x}=\dfrac{1(632.8·10^{-9})1.6}{0.004}=2.53·10^{-4}\text{ m}.$$