A Level Physics Practice Exam

Which equation correctly represents the relationship in a diffraction grating experiment?

1. n * wavelength = d / sinX

2. n * wavelength = d * sinX

3. wavelength = d * n / sinX

4. wavelength = n * d * sinX

The correct answer is: n * wavelength = d * sinX

The relationship in a diffraction grating experiment is accurately represented by the equation n * wavelength = d * sinX. Here’s why this is the case: In a diffraction grating setup, light is incident on a grating with a specific spacing, represented by d, which is the distance between adjacent slits. When light passes through these slits, it diffracts, creating an interference pattern on a screen. The angle of diffraction for the nth order maximum is given by the relationship that involves the wavelength of the light, the slit separation (d), and the angle of diffraction (X). The formula n * wavelength = d * sinX establishes that the path difference between light waves coming from adjacent slits is related to the angle at which constructive interference (maxima) occurs. The factor n represents the order of the maximum, which is an integer (1, 2, 3, etc.) indicating the position of the bright fringe. Thus, when rearranging this equation, it clearly shows that the product of the order number (n) and the wavelength must equal the product of the slit spacing (d) and the sine of the angle (X) at which the maxima appear. This equation is fundamental in the study of wave