Answer:
29.775°
1.911
Explanation:
Law of refraction(Snell's law):
n_1 sin Ф_1 = n_2 sin Ф_2
n_1 = The index of refraction for material with incident light,
n_2 = The index of refraction for material with refracted light
Ф_1= angle of incidence,
Ф_2 = angle of refraction.
Note: the angle is measured from the normal: a line drawn perpendicular to the surface at the point where the incident ray strikes the surface.
The Part of the light which continues into the second medium is transmitted rather than reflected, but the transmitted ray changes direction as it crosses the boundary. The transmission of light from one medium to another, but with a change in direction, is called refraction. The angles of the incidence and reflected light is described by (Snells law) which is shown above.
a)
n_3 = 1.329 —> for metalmol —> from table
1 —> in air
2 —> in the glass
3 —> in methanol
from air to glass
n_1 sin Ф_1 = n_2 sin Ф_2
1 x sin 41.3° = 1.550 sin Ф_2
Ф_2 = arcsin(1*sin41.3°/1.550) = 25.201°
from glass to methanol:
n_2 sin Ф_2 = n_3 sin Ф_3
1.550 sin 25.201° = 1.329 * sin Ф_3
Ф_3 = arcsin(1.550 sin 25.201°/1.329) = 29.775
from glass to unknown:
n_2 sin Ф_2 = n_3 sin Ф_3
1.550 sin 25.201° = n_unknown * sin 20.2
n_unknown = 1.550 sin 25.201°/sin 20.2
= 1.911
