Answer:
a ) Its wavelength decreases
Explanation:
When a ray enters into air from glass slab its wavelength decreases.
This is not an answer I'm sorry i just need points to ask my questions
The Hertzsprung- Russel diagram is used to how the relationship between the absolute magnitudes of stars and their effective temperatures.
Use a graduated cylinder filled halfway with water. Place the object inside, and measure the difference of the water level before and after you put said object in the water.
...Also this is elementary/middle school science