Question

1. You made two determinations of the wavelength of the bright green mercury line, one based on the first order interference and the other based on the second order interference. Which one do you think is more precise? Explain why.

2. Why is the wavelength of the spectral lines that seem same color have slightly different wavelength when emitted by different element?

3. List some diffraction phenomena in your daily life experience.

4. What does the spectrum from sunlight look like in the spectrometer? Give your thoughts comparing the spectrum with the white light from mercury?

Answer 1

1)The colors of these first orders are clearer, whilst those of the higher orders are diffuse. This is because, for the first order colors, the retardations are small and can only be multiples of one particular wavelength. On the other hand, the high colors represent very high retardations which may be multiples of more than one wavelength. So, we can say that first order interference measurement is more precise.

2)Every atom has its own distinct set of energy levels. Since a specific photon wavelength gives us a specific color, so different element emits slightly different wavelength.

3) (a) The setting sun appears to be red because of the diffraction of light from dust particles in the atmosphere.

(b) The rainbow pattern on compact disks or DVDs is also an example of diffraction of light

(4)Sunlight is made up of different wavelengths of visible colors. So, we see a continuous spectrum with many colors having vertical dark lines while in case of light from mercury, some of the strongest lines are in the ultraviolet and don’t contribute to the color in the visible. It forms a line spectrum(They emit primarily in the blue and green).