Wave Optics

Q1.In a Young's double slit experiment with λ = 500 nm, d = 0.5 mm, D = 1.5 m, the distance between the 2nd bright fringe and the 3rd dark fringe on the same side of the central maximum is:

• A0.25 mm
• B0.75 mm
• C0.5 mm
• D1.5 mm

Q2.In Young's double slit experiment, if the two slits are illuminated by two separate (independent) sodium lamps instead of a single source through one slit, the result is:

• AFringes with double brightness
• BNarrower fringes
• CNo interference fringes
• DFringes with half the width

Q3.According to Huygens principle, each point on a wavefront acts as:

• AA sink of energy
• BA source of secondary wavelets
• CA stationary node
• DA point of zero displacement

Q4.Monochromatic light of wavelength 589 nm in air enters water (n = 1.33). What is the wavelength in water?

• A782.4 nm
• B443 nm
• C589 nm
• D300 nm

Q5.The wavelength of light in a medium of refractive index n compared to its wavelength in vacuum is:

• Aλ_medium = n λ_vacuum
• Bλ_medium = λ_vacuum/n
• Cλ_medium = λ_vacuum
• Dλ_medium = λ_vacuum√n