When the distance between the screen and the double slits decreases in a Young double-slit experiment, the effect on the fringe width depends on the specific setup and conditions of the experiment. However, in general, reducing the distance between the screen and the slits leads to an increase in the fringe width.
The fringe width refers to the spacing between adjacent bright or dark fringes in the interference pattern. It is determined by the wavelength of the light used and the distance between the double slits.
In the Young double-slit experiment, the fringe width is given by the formula:
w = λD / d
where:
- w is the fringe width,
- λ is the wavelength of light used,
- D is the distance between the double slits and the screen,
- d is the separation between the double slits.
When the distance D is decreased while keeping the other parameters constant, the fringe width w increases. This means that the bright and dark fringes become wider apart on the screen.
Intuitively, this can be understood as follows: when the screen is closer to the slits, the light waves have less distance to travel, resulting in a wider spread of the interference pattern on the screen.
It's important to note that the fringe width also depends on the wavelength of light used and the separation between the double slits. So, while decreasing the distance between the screen and slits generally increases the fringe width, other factors can influence the precise behavior of the interference pattern.