Q35 / 237 · NTA Abhyas (NEET) 2020 · Physics · Ray Optics

The frequency of a light wave in a material is 2 × 1014 Hz and wavelength is 5000 A∘ . The refractive index of material will be

  • A
    1.40
  • B
    1.50
  • Correct answer
    C
    3.00
  • D
    1.33

Solution

The velocity of light water in the material is

v=vλ      …i

Refractive index of the material is

μ=cv       …ii

Where c is the speed of light in vacuum or air

or μ=cvλ     …iii

Given, v=2×1014 Hz,

λ=5000 Å=5000×10-10 m

c=3×108m s-1

Hence, from Eq (iii), we get

μ=3×1082×1014×5000×10-10=3.00

Hence, the correct answer is option: 'C'.

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