A parallel beam of white light is incident normally on a diffraction grating. It is noted that the second-order and third-order spectra partially overlap. Which wavelength in the third-order spectrum appears at the same angle as the wavelength of 600 nm in the second-order spectrum?
Correct answer: B. 400 nm
- A. 300 nm
- B. 400 nm
- C. 600 nm
- D. 900 nm
- E. 950 nm
Explanation
The explanation is given below:The wavelength in the third-order spectrum is 400nm.Where,n₁=initial order of the spectran₂=final order of the spectraλ₁=initial wavelength of the spectraλ₂=final wavelength of the spectraFrom the question we have,n₁=2λ₁=600nmn₂=3By substituting the required values in equation (1) we get;Hence, the wavelength in the third-order spectrum is 400nm.
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Light is studied through reflection, refraction, dispersion, interference, diffraction and polarization, linking ray behavior with its wave nature. Questions may involve mirrors, lenses, optical instruments, refractive index and image formation, while geometrical optics deals with rays and wave optics explains effects such as interference and diffraction.
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