Most Important Selected Qs for JEE AdvancedPhysicsWave Optics
A B C is a spherical wave front centred at O symmetric about B E is incident on silts S₁ and S₂ . B S₁=3 , S₁ S₂=4 , B O=6 , S₁ E=128 and is the wavelength of incident wave. A mica sheet of refractive index 1.5 is pasted on S₂ . The minimum value of thickness of mica sheet for which central bright fringe forms at E will be
Options
- A31 8
- B15 8
- C5 8
- D7 8
Correct answer
A. 31 8
Step-by-step solution
aligned & O S₁=3 & O S₂=5 aligned S₂ leads S₁ by 2 Net phase at E must be zero aligned & -2 + (128 )^2+(4 )^2 -128 +t / 2=0 & t / 2= 31 16 t= 31 8 aligned