Diffraction Grating

Pick an option to see whether it holds. If one of them stops you, the theory page is two steps back.

1. 01

   The diffraction grating equation is given by:

   • a) (a+b) cos θ = nλ
   • b) n sin θ = (a+b) λ
   • c) (a+b) sin θ = nλ
   • d) (a+b) tan θ = nλ
2. 02

   The grating element (a+b) refers to:

   • a) The distance between two consecutive slits (rulings) on the grating
   • b) The number of lines per unit length on the grating
   • c) The width of a single slit
   • d) The distance between the grating and the telescope
3. 03

   If a grating has 5000 lines per cm, the grating element (a+b) is:

   • a) 5000 cm
   • b) 5 × 10⁻⁵ cm
   • c) 5 × 10³ cm
   • d) 2 × 10⁻⁴ cm
4. 04

   In the diffraction grating experiment, the spectrometer must first be adjusted for:

   • a) Minimum deviation
   • b) Maximum intensity
   • c) Parallel rays (normal/parallel adjustment of telescope, collimator, and grating table)
   • d) Total internal reflection
5. 05

   For normal incidence, the grating is set so that its plane is:

   • a) Parallel to the incident beam
   • b) At 45° to the incident beam
   • c) At the Brewster angle
   • d) Perpendicular to the incident parallel beam of light
6. 06

   As the order of diffraction (n) increases, the angle of diffraction (θ) for a given wavelength:

   • a) Remains constant
   • b) Increases
   • c) Decreases
   • d) Becomes zero
7. 07

   The zero order image in a diffraction grating spectrum represents:

   • a) The first-order diffracted beam
   • b) The point of maximum diffraction
   • c) An artifact due to grating defects
   • d) The undeviated, undispersed central image
8. 08

   The phenomenon where two different wavelengths are diffracted at slightly different angles in the same order (used to distinguish spectral lines) is called:

   • a) Dispersion
   • b) Polarization
   • c) Interference
   • d) Scattering
9. 09

   A diffraction grating with a larger number of lines per cm (smaller grating element (a+b)) produces:

   • a) No change in resolving power
   • b) Only first-order spectra
   • c) Lower resolving power and smaller angular separation
   • d) Higher resolving power and greater angular separation between spectral lines
10. 10

    In the formula (a+b) sin θ = nλ, the wavelength λ can be calculated using:

    • a) λ = (a+b) sin θ
    • b) λ = n / [(a+b) sin θ]
    • c) λ = (a+b) / sin θ
    • d) λ = (a+b) sin θ / n