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Question 18N.3.SL.TZ0.10a.ii

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Date November 2018 Marks available [Maximum mark: 1] Reference code 18N.3.SL.TZ0.10a.ii
Level SL Paper 3 Time zone TZ0
Command term Suggest Question number a.ii Adapted from N/A
a.ii.
[Maximum mark: 1]
18N.3.SL.TZ0.10a.ii

An optic fibre consists of a glass core of refractive index 1.52 surrounded by cladding of refractive index n. The critical angle at the glass–cladding boundary is 84°.

(a.ii)

The refractive indices of the glass and cladding are only slightly different. Suggest why this is desirable.

[1]

Markscheme

to have a critical angle close to 90° ✔

so only rays parallel to the axis are transmitted ✔

to reduce waveguide/modal dispersion ✔

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