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Two wavelengths of sodium light 590 nm and 596 nm are used, in turn, to study the diffraction taking place at a single slit of aperture 2×10⁻⁴m. The distance between the slit and the screen is 1.5 m. Calculate the separation between the positions of the first maxima of the diffraction pattern obtained in the two cases.

User Jessee
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Final answer:

To find the separation between the positions of the first maxima for two different wavelengths, we calculate the position of each maximum using the formula y = (Lλ)/d and then find their difference. The separation for the 590 nm and 596 nm wavelengths is 45 μm.

Step-by-step explanation:

To calculate the separation between the positions of the first maxima for sodium light wavelengths of 590 nm and 596 nm in a diffraction experiment, we need to use the diffraction formula for a single slit: d sin(θ) = mλ, where d is the slit aperture, θ is the angle of the diffraction maximum, m is the order number of the maximum, and λ is the wavelength of the light.

In this case, the order of the maximum m is 1, since we are looking for the first maxima. The aperture width d is given as 2×10−4 m. The distance L from the slit to the screen is 1.5 m. The position y of a maximum on the screen is related to the angle θ through the relationship y = L tan(θ), but if the angle is small (which is generally true for diffraction patterns), we can approximate tan(θ) with sin(θ): y ≈ L sin(θ).

For the first maximum m = 1, the position is given by: y = (Lλ)/d. Thus, we compute the positions of the maxima for the two wavelengths separately and then find their separation as the difference between the two positions.

Using the provided wavelengths:

  • For λ = 590 nm: y590 = (1.5 m × 590×10−9 m) /(2×10−4 m) = 4.425×10−3 m
  • For λ = 596 nm: y596 = (1.5 m × 596×10−9 m) /(2×10−4 m) = 4.470×10−3 m

The separation between the two first maxima is the difference of these two positions:

Separation = |y596 - y590| = |4.470×10−3m - 4.425×10−3m| = 4.5×10−5m or 45 μm

User Strong Like Bull
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