Light travels at a speed of 2.201 × 108 m/s in a certain substance. What substance from Table could this be? For the speed of light in a vacuum use 2.998 × 108 m/s, show your calculations.

Substance Index of

Refraction, n

Solids at 20°C

Diamond .........2.419

Glass, crown .......1.523

Ice (0 °C) .........1.309

Sodium chloride ......1.544

Quartz

Crystalline ........1.544

Fused ..........1.458

Liquids at 20°C

Benzene .........1.501

Carbon disulfide .......1.632

Carbon tetrachloride ....1.461

Ethyl alcohol .........1.362

Water ..........1.333

Gases at 0°C, 1 atm

Air ...........1.000 293

Carbon dioxide ......1.000 45

Oxygen, O2 ......1.000 271

Hydrogen, H2 .....1.000 139