engineering recuitment GATE ECE 2023-24 Test Series Electromagnetic Theory Waveguides and Guided Waves Optical Fiber
The change in acceptance angle and numerical aperture for an optical fibre having core diameter of 80 μm and numerical aperture of 0.65 in air, when placed in water (μ = 1.33) is
1
N.A remains same, 29.25°
2
NA becomes 1.33 times, 40.54°
3
NA remains same, 11.28°
4
\({\rm{NA\;becomes}}\frac{1}{{1.33}}{\rm{time}},{\rm{\;}}29.25^\circ \)