25 (c) Infrared radiation can travel along an optical fibre. Look at the table. It shows some properties of materials A, B, C and D. Material
Does total internal reflection happen?
Is Multiplexing possible?
Channel speed in bits per second
A
yes
yes
100 × 109
B
no
yes
171 × 109
C
yes
yes
146 × 109
D
no
no
273 × 109
The channel speed is the number of bits of information transferred per second. Which material is the best for making optical fibres? Choose from A B C D. ........................ Explain your answer. ................................................................................................................................................... ................................................................................................................................................... ................................................................................................................................................... ............................................................................................................................................. [2]
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