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In figure, the optical fibre is l = 2 m ...

In figure, the optical fibre is l = 2 m long and has a diameter of ` d = 20 mu m.` If a ray of light is `theta_1 = 40^@`, the number of reflections it makes before emerging from the other end is1.31 and `sin 40^@ = 0.64)`

A

55000

B

66000

C

45000

D

57000

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