Optical fibres are used to transmit digital signals using infrared radiation.
The average refractive index of the fibres is 1.25.
Which row describes a digital signal and gives the speed of infrared radiation in the fibres?
| digital signal | speed of infrared radiation in the fibres / m s−1\text{m s}^{-1}m s−1 | |
|---|---|---|
| A | a signal that consists of a continuous range of values | 2.4 × 108 |
| B | a signal that consists of only two values | 2.4 × 108 |
| C | a signal that consists of only two values | 3.8 × 108 |
| D | a signal that consists of a continuous range of values | 3.8 × 108 |
Row A
Row B
Row C
Row D
216 exam-style questions on CIE IGCSE Physics 3.2 Light, covering 3.2.1a Reflection of light, 3.2.1b Images in a plane mirror, 3.2.2 Refraction of light, 3.2.2a Refraction of light, 3.2.2b Total internal reflection, 3.2.2c Refractive index and critical angle, 3.2.2d Optical fibres, 3.2.3a Converging and diverging lenses, 3.2.3b Ray diagrams and the nature of images, 3.2.3c Virtual images and the magnifying glass, 3.2.3d Correcting long-sightedness and short-sightedness, and 3.2.4 Dispersion of light. Each one has a worked solution and a mark scheme showing where the marks go.