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    Question

    In a diffraction experiment using a single slit, the

    angular width of central maximum decreases when:
    A Wavelength increases Correct Answer Incorrect Answer
    B Slit width increases Correct Answer Incorrect Answer
    C Distance to screen increases Correct Answer Incorrect Answer
    D Light intensity decreases Correct Answer Incorrect Answer

    Solution

    In a single-slit diffraction experiment, the central maximum is the bright fringe at the center of the diffraction pattern. The angular width of this central maximum is defined as the angle between the first minima on either side of the central peak, and it is given by: Angular width = 2θ = 2λ / a,
    where:

    • λ is the wavelength of the light used
    • a is the width of the slit
    From this equation, we observe that the angular width:
    • Increases when the wavelength (λ) increases
    • Decreases when the slit width (a) increases
    Therefore, when the slit width increases, the angle θ becomes smaller, and thus the central maximum becomes narrower — meaning the angular width decreases.

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