An object moving in a circle at constant speed (Choose a correct option with some nice explanation!) a) must have only one force acting on it.
b) is not accelerating.
c) is held to its path by centrifugal force.
d) has an acceleration of constant magnitude.

ABSURB ANSWERS ARE GONNA GET REPORTED. THAT'S IT

an object is moving at constant speed then it has no acceleration.

Explanation:

This is indeed true in the case of an object moving along a straight line path. On the other hand, a particle moving on a curved path is accelerating whether the speed is changing or not. Velocity has both magnitude and direction.

But Than Again when a object moves in a circle at a constant speed its velocity (which is a vector) is constantly changing. Its velocity is changing not because the magnitude of the velocity is changing but because its direction is.

Hope this was helpful∵

your answer is, orbit around the nucleus

speed of light in vacuum is 300,000 km/s

speed of light in other mediums is given by the expression v = c/n, where c is the speed of light in vacuum and n is the refractive index of medium.

for the first medium v = 200,000 km/s

  so, refractive index of medium = 300000/200000 = 1.5

    1.5 refractive index is usually for glass. so first medium is glass.

for the second medium v = 250,00 km/s

so, refractive index of medium = 300000/250000 = 1.2

    1.2 refractive index is usually for water. so second medium is water.

for the third medium v = 0 km/s

so, refractive index of medium = 300000/0 = ∞

    ∞ refractive index is usually for opaque mediums. so third medium is opaque medium.