Virtual Labs

Fraunhofer Diffraction using Single-Slit and Circular Aperture

1. Which of the following best describes Fraunhofer diffraction?

a: Light scattering from a rough surface Explanation

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b: Bending of light as it travels past a sharp edge. Explanation

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c: Absorption of specific wavelengths of light by a material Explanation

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d: Change in the colour of light as it passes through a prism Explanation

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2. In Fraunhofer diffraction, what is the key characteristic of the light source and observation screen?

a: They are located very close to the diffracting object Explanation

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b: The light source is a point source, and the screen is placed at the focal point of a lens Explanation

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c: The light source is distant, and the screen is placed far away from the diffracting object. Explanation

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d: The light source is monochromatic, and the screen is highly reflective. Explanation

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3. In Fraunhofer diffraction at a single slit, what determines the angular position of the first minimum?

a: Slit width and wavelength of light Explanation

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b: Distance between the slit and the screen Explanation

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c: Intensity of the light source Explanation

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d: Refractive index of the medium Explanation

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4. What happens to the central maximum in single-slit Fraunhofer diffraction when the slit width is reduced?

a: The central maximum becomes narrower Explanation

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b: The central maximum becomes wider Explanation

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c: The central maximum disappears Explanation

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d: The central maximum remains unchanged Explanation

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5. In a diffraction grating experiment, what happens when the number of slits is increased?

a: The fringes become blurred Explanation

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b: The fringes become sharper and more intense Explanation

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c: The central maximum vanishes Explanation

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d: No diffraction occurs Explanation

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6. Fraunhofer diffraction is also known as which type of diffraction?

a: Near-field diffraction Explanation

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b: Far-field diffraction Explanation

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c: Contact diffraction Explanation

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d: Circular diffraction Explanation

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7. What is the condition for the second minimum in single-slit Fraunhofer diffraction?

a: d sinθ = λ/2 Explanation

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b: d sinθ = 2λ Explanation

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c: d sinθ = 3λ/2 Explanation

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d: d sinθ = 3λ Explanation

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8. The diffraction pattern produced by a circular aperture is called:

a: Newton's rings Explanation

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b: Interference fringes Explanation

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c: Airy pattern Explanation

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d: Fresnel fringes Explanation

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9. Which formula correctly represents the intensity distribution in single-slit Fraunhofer diffraction?

a: I = I₀ cos²(α), where α = πd sinθ / λ Explanation

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b: I = I₀ (sinα / α)², where α = πd sinθ / λ Explanation

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c: I = I₀ sin²(2α), where α = πd sinθ / λ Explanation

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d: I = I₀ / α² Explanation

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10. A slit of width d = 0.20 mm is illuminated by light of wavelength 500 nm. The angular position of the first minimum is approximately:

a: 0.143° Explanation

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b: 0.286° Explanation

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c: 0.572° Explanation

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d: 0.072° Explanation

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