Question

A small table of values is presented below for selection of angles (measured in degrees). A light beam passes from air into a fluid with an unknown index of refraction. The angle of incidence is 30 degrees, the index of refraction of air is 1.00, and the angle of refraction 15 degrees. Calculate the index of refraction for the fluid. a.)1.21 b.)1.93 c.)3.14 d.)1.57 A light beam passes from water (angle of incidence = 45 degrees; n = 1.33) into oil (angle of refraction = 30 degrees; n = ?). Calculate the index of refraction for the oil. a.)1.15 b.)2.23 c.)1.62 d.)1.88 A monochromatic beam of light (monochromatic means just one wavelength present) is traveling through a region of space where the index of refraction is 1.50 and enters a region of space filled with air (index of refraction for air can be considered to be equal to 1.00 for these types of problems. Therefore the speed of light for this light beam a.)increases b.)remains the same. c.)decreases d.)both increases and decreases A monochromatic beam of light (wavelength = 490 nanometers) is travelling through air. The beam then enters a region of space where the index of refraction is 1.30 and therefore the wavelength for this light beam a.)increases by a factor of 1.30 b.)remains the same. c.)decreases by a factor of 1.30 d.) neither increases decreases nor stays the same A monochromatic beam of light (wavelength = 550 nanometers) is traveling through air. The beam then enters a region of space where the index of refraction is 1.50 and therefore the frequency for this light beam a.)increases by a factor of 1.50 b.)remains the same. c.)decreases by a factor of 1.50

Answer 1

1)

We use Snell's law of refraction

n1 sin theta 1 = n2 sin theta 2

n2 = n1 * sin theta 1/ sin theta 2

n2 = sin 30 / sin 15 = 1.93

2)

We use Snell's law of refraction

n1 sin theta 1 = n2 sin theta 2

n2 = n1 * sin theta 1/ sin theta 2

n2 = 1.33 *sin 45 / sin 30 = 1.88

3)

Since it moves from a denser to rarer medium, Speed INCREASES

4)

C

Decreases to keep Frequency constant, as velocity decreases

5)

B

Frequency Remains the Same