This video shows how to calculate the speed that light will travel at in a material with a known value of refractive index. Consumer ovens like the one in our kitchen are typically rated at 2450 MHz or 2450000000 245 billion hertz. If the velocity is non-uniform all you can say is what the average speed is.
This index measures how much the medium alters the course that the light travels through reflection refraction occlusion or other obstruction.
A small bulb is placed at the bottom of a tank containing water to a depth of 1 m. The speed of light called c is given by this formula. This vacuum speed of light c is what the statements from relativity describeWhenever light is in a vacuum its speed has that exact value no matter who measures it. In 1676 he determined that this phenomenon was due to the fact that the speed of light was finite and subsequently estimated its velocity to be approximately 220000 kms.