A double slit arrangement is illuminated first with red, then with blue light.
a. which one has wider fringes?
b. which one produces more fringes?
To determine which color, red or blue light, has wider fringes in a double-slit arrangement, we need to consider diffraction.
a. Wider fringes correspond to smaller diffraction angles. The diffraction angle can be calculated using the equation:
sin(θ) = mλ/d,
where θ is the diffraction angle, m is the order of the fringe, λ is the wavelength of light, and d is the distance between the slits.
Since red light has a longer wavelength than blue light, and the diffraction angle is inversely proportional to the wavelength, we can conclude that red light will produce wider fringes compared to blue light.
b. To determine which color light produces more fringes, we need to consider the relationship between the fringe number and the angle of observation.
The number of fringes can be calculated using the equation:
N = Lλ/d,
where N is the number of fringes, L is the length of the screen, λ is the wavelength of light, and d is the distance between the slits.
Since the number of fringes depends on both the wavelength and the length of the screen, we cannot definitively say which color produces more fringes without additional information. The length of the screen and the distance between the slits need to be specified.