Answer:
-the ratio of the speed of light
in air to the speed of light in the substance.
-speed of light in air 300,000 km/sec, which decreases when it passes through a transparent substance.
-e.g.. speed of light in substance = 200,000 km/sec, R.I. = 300,000/200,000 = 1.5
Explanation:
That's an urban legend that's been around for a long time.
It was tested on "Mythbusters". The conclusion was that
it would sting pretty good, and maybe raise a lump, but
it would never penetrate the skull, and it couldn't kill.
D: Refraction
Explanation: Refraction occurs when a medium bends the light rays of an object. Like water for instance as an example of a medium.
Answer:
Option (b) is correct.
Explanation:
The motion under the influence of gravity is called projectile motion.
The acceleration due to gravity is constant through out the motion and it is always acting downwards.
When an athlete jumps and follow the projectile path, it always have the same horizontal velocity as there is no acceleration in the horizontal direction.
Also he has the vertical acceleration constant which is equal to the acceleration due to gravity and acts towards the center of earth.
Option (b) is correct.