# Physics

posted by on .

A mixture of light with wavelength 540 nm and light with wavelength 400 nm is aimed at a pair of slits to produce a double-slit interference pattern. Which of these will be true?

The pattern will be the same for both wavelengths.

The central maximum will be at the same position for both, but the first maximum to each side will be at different locations.

The central maximum and the first maximum to each side will be at different locations, but the other maxima will be the same.

Both the central maximum and all the maxima on each side will be different.

I've gone through all of my material, but it fails to mention what will happen if a mixture of light is used, please help!

• Physics - ,

Consider each wavelength as a separate problem. What is the separation for the different frequencies?

• Physics - ,

My material didn't go over how to find separation. However, it did specify that the difference in paths from the point of the first maximum (and the central maximum) is one wavelength. If I am following this bit of information correctly, then I presume that all of the maxima on each side would be different. Is this right?

• Physics - ,
• Physics - ,

True:
The central maximum will be at the same position for both, but the first maximum to each side will be at different locations.

• Physics - ,

Elena, could you explain why you chose this answer?

• Physics - ,

I've figured that all other maximum will occur at different locations. But, would the central maximum occur at the same location for both of these wavelengths?

• Physics - ,

Yes, the central maxima are in the same place. The others are not (for a given order n)

Sometimes a lower order of the longer wavelength will coincide with a higher order of the shorter wavelength.