Question

Light from a small region of an ordinary incandescent bulb is passed through a yellow filter and

then serves as the source for a Young's double-slit experiment. Which of the following changes
would cause the interference pattern to be more closely spaced?
A. Use slits that are closer together
B. Use a light source of lower intensity
C. Use a light source of higher intensity
D. Use a blue filter instead of a yellow filter
E. Move the light source further away from the slits.

Answer 1

In a Young's double-slit experiment, using a blue filter instead of a yellow filter will result in light with a shorter wavelength, thus causing the interference fringes to be more closely spaced.

Step-by-step explanation:

To determine which changes would cause the interference pattern in a Young's double-slit experiment to be more closely spaced, you must understand the relationship between slit separation, wavelength of light, and the interference pattern. According to the principles of wave interference:

• Slits closer together (d smaller) result in a broader interference pattern.
• A blue filter produces light with a shorter wavelength than yellow light.
• The wavelength is directly proportional to the fringe spacing in the interference pattern.

So, changing the filter to blue will result in light with a shorter wavelength. This will cause the interference fringes to be more closely spaced since the fringe spacing is inversely proportional to the wavelength of light used. Therefore, the correct answer is D. Use a blue filter instead of a yellow filter.

Options such as using a light source of lower or higher intensity won't affect the spacing, as the intensity does not change the wavelength. Moving the light source further away from the slits also has no effect on the fringe spacing since the distance from the source to the slits does not change the characteristics of the light passing through the slits.