In a perfect vacuum, light waves travel at 300,000 kilometers every second. when light waves travel through materials, such as air, they a.speed up b.slow down c.increase in amplitude d.heat up

c = speed of light in vacuum = 300,000 kilometers/second

n = index of refraction of material

v = speed of light in the material

Speed of light in a given material is given as

v = C/n

v = 300,000/n

for air, the value of index of refraction "n" is slightly greater, hence the speed of light in air is smaller than 300,000 kilometers/second. hence the light waves slow down.

so correct choice is

B.slow down

Answer : Centripetal force is 1363.6 N

Explanation :

It is given that,

Mass of the person,

Radius of the circular path,

Person's tangential speed,

Centripetal force acting on the person is :

So, the centripetal force acting on the person is 1363.6 N

Hence, this is the required solution.