Index of Refraction

Homework Answers

The index of refraction is a number that gives you a clue about how light will travel though a substance. The index of refraction is inversely proportional to the speed of light through a substance, and can be calculated with the following formula:

n = C/Cn

where n is the index of refraction, C is the speed of light (C = 3.00 X 108), and Cn is the speed of light through the medium, substance.

If you know the index of refraction, you can calculate the speed of light through a medium by solving the above formula for Cn, which gives you

Cn = C/n

Using the above formulas, fill in the following table.

Table 1

Medium

(Substance)

N

Cn

Hydrogen

1.661

1.806 X 10 8

Chlorine

1.385

2.166 X 10 8

Mercury

1.600

1.875 X 10 8

Mercury chloride

1.725

1.739 X 10 8

Oxygen

1.221

2.457 X 10 8

Nitrogen

1.205

2.490 X 10 8

Carbon Dioxide (CO2)

1.195

2.510 X 10 8

Gold sodium chloride

1.545

1.942 X 10 8

Magnesium ammonium sulfate

1.461

2.053 X 10 8

Acetone (Fingernail Polish Remover)

1.357

2.211 X 10 8

Ethanol

1.359

2.208 X 10 8

Isopropyl alcohol

1.375

2.182 X 10 8

Butyl stearate (oil)

1.442

2.080 X 10 8

Water

1.333

2.251 X 10 8

Rock Salt

1.893

1.585 X 10 8

Sodium chloride (table salt) in water solution

1.378

2.177 X 10 8

Air (15OC)

1.391

2.157 X 10 8

Quartz Glass (18OC)

1.574

1.906 X 10 8

Sucrose (10% cane sugar at 20OC)

1.479

2.028 X 10 8

  1. Examining the above table, what are the 5 mediums in which light travels the slowest?
  2. In the mediums rock salt, hydrogen, mercury chloride, mercury, and quartz glass light travels the slowest.

  3. Examining the above table, what are the 5 mediums in which light travels the fastest?
  4. In the mediums oxygen, nitrogen, carbon dioxide, water, and ethanol light travels the slowest.

  5. Examining the above table, and recalling your index of refraction home lab, did your results match the change in the speed of light in your medium?

This is your opinion, backed up by the above information about the index of refraction.



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