Try not to imagine light as like a Baseball that slows down as it hits a denser medium (like water), and then (seemingly impossibly) speeding up as it goes back to a less dense medium (like air).
Light should instead be viewed as an electromagnetic wave, a wave that can be altered by the charged particles within a medium. How that EM wave is altered depends on the frequency with which the wave is vibrating and the nature of the charged particles in the medium.
When you do the calculations rigorously, you find that water molecules will cause this wave to propogate less slowly. When it leaves the water into air, almost no charged particles exist to alter the speed of propogation of this wave -- it instead travels at the speed Maxwell said such an EM wave would propogate.
When light with wavelength of 589 nanometers moves through water at the temperature of 20° C, its speed is 75% of the speed of light in vacuum.
That would depend what it enters from. If the light is transitioning from air to water,its speed decreases. If it's going from jello to water, its speed increases.
No. Light slows down whenever it passes through water. Nothing is faster than the speed of light in a vaccum.
The speed of light depends on the electrical properties of whatever substance it's in. It has nothing to do with what substance it used to be in before, or what substance it's going into next. -- If it goes from air into vacuum, its speed increases. -- If it goes from air into water, its speed decreases. -- If it goes from water into air, its speed increases. -- If it goes from water into diamond or jello, its speed decreases.
The speed of light through vacuum is constant. The speed of light through air is slightly less. The speed of light through water or some other medium is even less than that. The factor by which the speed of light (and its wavelength) is reduced within a medium is called the "index of refraction" (which determines the amount of bending that occurs when light goes from one medium to another).
No, light does not speed up in water, it slows down.
When light with wavelength of 589 nanometers moves through water at the temperature of 20° C, its speed is 75% of the speed of light in vacuum.
It means that the speed of light through water at that temperatureis [ (the speed of light through vacuum) divided by (1.333) ].
That would depend what it enters from. If the light is transitioning from air to water,its speed decreases. If it's going from jello to water, its speed increases.
The speed of light is constant
No. Light slows down whenever it passes through water. Nothing is faster than the speed of light in a vaccum.
The speed of light depends on the electrical properties of whatever substance it's in. It has nothing to do with what substance it used to be in before, or what substance it's going into next. -- If it goes from air into vacuum, its speed increases. -- If it goes from air into water, its speed decreases. -- If it goes from water into air, its speed increases. -- If it goes from water into diamond or jello, its speed decreases.
Yes it is true. If c is the speed of light in air then in water it will be 3/4 of c Hence refractive index of water = speed of light in air/speed of light in water So refractive index = 4/3 = 1.333
The speed of light through vacuum is constant. The speed of light through air is slightly less. The speed of light through water or some other medium is even less than that. The factor by which the speed of light (and its wavelength) is reduced within a medium is called the "index of refraction" (which determines the amount of bending that occurs when light goes from one medium to another).
The light refracts due to the change in speed. The change in speed occurs because the light is travelling through a denser medium. So it will travel fastest through the air and slowest through the glass
The speed of light in a vacuum is constant. Otherwise, the speed of light will depend on what materials it travels through. For example, the speed of light in air is similar to the speed of light in a vacuum; in water, it is quite a bit slower.
According to the light spectrum, water should travel through a more violet coloured water the fastest. The speed of light through a medium is not governed by its wavelength, so colour is not a factor.