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Question: Answered & Verified by Expert
A light wave is incident normally on a glass slab of refractive index 1.5. If 4% of light gets reflected and the amplitude of the electric field of the incident light is 30 Vm, then the amplitude of the electric field for the wave propagating in the glass medium will be:
PhysicsRay OpticsJEE MainJEE Main 2019 (12 Jan Shift 1)
Options:
  • A 30Vm
  • B 6Vm
  • C 24Vm
  • D 10Vm
Solution:
1540 Upvotes Verified Answer
The correct answer is: 24Vm
n= refractive index   =εrμr
I=12ε0E02C

I=12ε E2V

I=0.96I

12εE2v=0.9612ε0E02C

E=0.96ε0ε0εrcvE0

(For most of the transparent medium μr1 )
  E=0.96 . 1εrμr. cvE0

=0.96.1n. n E0

E=0.96n E0E=0.961.5×30=24 Vm

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