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Punjab (PTB) · Chapter test · Free

2nd Year Physics Chapter 3 TestPHYSICAL OPTICS

30 marks · 40 minutes · 21 questions. Covers: CHAP 15: PHYSICAL OPTICS.

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2nd Year Physics Chapter 3 Test

2nd Year · Physics · Punjab (PTB)

Name: ____________Roll No: ________Class/Section: ________Date: ________Total marks: 30Time: 40 minutes

Q1. Multiple choice questions (Attempt all · 10 × 1 = 10)

  1. An array of a large number of parallel slits with equal width and equal spacing between centers is called a:

    1. Plano-convex lens

    2. Rubens tube

    3. Diffraction grating

    4. Michelson interferometer

  2. Who constructed the first diffraction grating using fine wires?

    1. Thomas Young

    2. James Clerk Maxwell

    3. Christiaan Huygens

    4. Joseph von Fraunhofer

  3. When white light shines on a thin film, different colors appear because different colors have different:

    1. Wavelengths

    2. Amplitudes

    3. Speeds in vacuum

    4. Intensities

  4. When we increase the number of slits in an interference experiment, the positions of the maxima remain the same, but they become:

    1. Progressively wider

    2. Progressively narrower

    3. Inverted

    4. Completely dim

  5. At Point B (the mid-point of the first dark fringe), the two light rays are in:

    1. Phase with each other

    2. Antiphase

    3. Constant acceleration

    4. Quadrature

  6. Which of the following is an everyday example of light interference:

    1. X-ray imaging of bones

    2. Sun rays passing through a lens

    3. Sound box resonance in a guitar

    4. Halos of light around street lamps on a foggy night

  7. The spacing d between the centers of adjacent slits in a grating is known as:

    1. Grating spacing

    2. Fringe width

    3. Wavelet radius

    4. Aperture diameter

  8. Bright fringes in light interference are the equivalent of which regions in sound interference?

    1. Quiet regions

    2. Loud regions

    3. High frequency regions

    4. Silent regions

  9. The beautiful bright bands of color seen on a soap bubble or oil floating on water are due to:

    1. Diffraction

    2. Interference

    3. Dispersion only

    4. Acoustic levitation

  10. Destructive interference (dark regions) occurs when the path difference is a:

    1. Whole integer number of wavelengths

    2. Half-integer number of wavelengths

    3. Continuous exponential of wavelengths

    4. Zero path difference

Q2. Short questions (Attempt any 6 of 8 · 6 × 2 = 12)

  1. Compare the usage of Huygens' principle with Maxwell's equations.

  2. State the three basic conditions required for two waves to produce a noticeable interference pattern.

  3. What does the principle of superposition predict when two identical sound waves arrive exactly in phase?

  4. How can constructive and destructive interference be detected in the microwave experiment?

  5. Define a "ray" in the context of wave motion.

  6. What are first-order and second-order lines in a diffraction grating pattern?

  7. What happens to the screen's pattern if you carefully cover up one of the two slits?

  8. Give two everyday examples of light interference.

Q3. Long questions (Attempt any 2 of 3 · 2 × 4 = 8)

  1. Two slits spaced 0.450 mm apart are placed 75.0 cm from a screen. What is the distance between the second and third dark lines of the interference pattern on the screen when the slits are illuminated with coherent light with a wavelength of 500 nm?

  2. Two very narrow slits are spaced 1.80 mm apart and are placed 35.0 cm from a screen. What is the distance between the first and second dark lines of the interference pattern when the slits are illuminated with coherent light of wavelength 550 nm?

  3. Describe the arrangement of Young's double slit experiment. Derive the expression for fringe width. How does it demonstrate the wave nature of light?