A researcher investigates how the angle of refraction of light in a semicircular container of liquid glycerol depends on the angle of incidence.
Table 1 shows some of the researcher's results.
| Angle of incidence (degrees) | Mean angle of refraction (degrees) |
|---|---|
| 20 | 14 |
| 40 | 26 |
| 60 | ZZZ |
| 80 | 42 |
For an angle of incidence of 60∘60^\circ60∘, the researcher's three measurements for the angle of refraction were: 34∘,37∘,37∘34^\circ, \quad 37^\circ, \quad 37^\circ34∘,37∘,37∘ Calculate the mean value Z Z\,Z to complete Table 1.
Complete the following sentence by choosing the correct word from the options: random, systematic, or zero.
"The researcher conducted three trials for each angle of incidence and calculated a mean to reduce the effect of __________ errors."
Using the data in Table 1, state whether the angle of refraction is less than, equal to, or greater than the angle of incidence.
Why is the researcher's conclusion only valid for angles of incidence between 20∘ 20^\circ\,20∘ and 80∘80^\circ80∘?
The researcher wants to compare the refraction caused by the glycerol with that of water. Which variable must the researcher keep the same for both liquids to ensure a fair comparison?
- The angles of incidence tested
- The volume of liquid in the container
- The duration of exposure to the light beam
- The material of the container walls