Single Slit Diffraction

Step 1: Understanding the Diffraction Pattern In a single slit diffraction experiment, the diffraction pattern is formed when light passes through a narrow slit and spreads out. The angular width of the central maximum is given by the formula: Where: - is the wavelength of the light, - is the width of the slit, - is the angle subtended by the central maximum. Step 2: Effect of Changing the Wavelength - The diffraction pattern depends on the wavelength of the light used. A longer wavelength results in a wider central maximum (larger angle ), and a shorter wavelength results in a narrower central maximum (smaller angle ). - Red light has a longer wavelength than blue light, so when red light is replaced by blue light, the wavelength decreases. - As a result, the angular width of the central maximum will decrease, and the fringes will become narrower and more closely spaced. Step 3: Conclusion The correct conclusion is that the fringes will become narrower and crowded together when red light is replaced by blue light. Thus, the correct answer is: