Passage IV

When waves of laser light pass through a narrow slit and onto a screen, they form a pattern of light and dark bands on the screen, as shown in Figure 1.

This phenomenon is called diffraction, and the pattern is called a diffraction pattern.

In each of the following studies of diffraction. students directed laser light through a slit, forming a diffraction pattern on a screen. They measured y1 the distance from the center of the brightest band in the pattern to the center of one of the 2 adjacent dark bands. In each study, x was the distance between the slit and the screen.

Study 1

In Trials 1-4, the slit width was varied, the wavelength of the laser light was fixed, and x was 6.00 m. The results are shown in Table 1.

Study 2

In Trials 5-8, the slit width was 0.24 mm, the wavelength (color)of the laser light was varied, and x was 6.00 m. The results are shown in Table 2.

Study 3

In Trials 9-12, the slit width was 0.24 mm, the wavelength was the same as in Study 1, and x was varied. The results are shown in Table 3.

21. For fixed values of wavelength and slit width, which of the following graphs best represents the relationship between y1 and x ?

Answer and Explanation

Your Answer is

Correct Answer is C

Explanation

To discuss the relationship between y1 and x under the same conditions of slit width and wavelength, you should refer to table 3;

From table 3, it can be seen that the larger x is, the larger y1 will be, so exclude A and Option B;

Secondly, when x=0, there is no possibility of diffraction, so you should choose C