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Monochromatic light passes through two narrow slits 0.23 mm apart and forms an interference pattern on a screen 2.13 m away. If light of wavelength 645.78 nm is used, what is the distance from the center of the central maximum to the center of the third order bright fringe in centimeters?

User Maksim
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1 Answer

3 votes

Given:

The distance between the two narrow slits is


\begin{gathered} d=\text{ 0.23 mm} \\ =2.3*10^(-4)\text{ m} \end{gathered}

The distance between the slit and the screen is


D=\text{ 2.13 m}

The wavelength of the light is


\begin{gathered} \lambda\text{ = 645.78 nm} \\ =645.78*10^(-9)\text{ m} \end{gathered}

Required: Distance of the third bright fringe from the central maximum.

Step-by-step explanation:

The third bright fringe will have m = 3.

The distance of the third bright fringe from the central maximum can be calculated by the formula


y=\frac{m\lambda\text{ D}}{d}

On substituting the values, the distance can be calculated as


\begin{gathered} y=(3*645.78*10^(-9)*2.13)/(2.3*10^(-4)) \\ =0.0179\text{ m} \end{gathered}

Final Answer: The distance of the third bright fringe from the central maximum is 0.0179 m.

User Osman Goni Nahid
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