G Only something with no mass (such as light) can move at the speed of light. b. Theoretically, a particle with mass can only move faster than the speed of light if given infinite energy. c. When in a medium (such as water) light will move less than c, and observers in different inertial frames can observe that light moving at different speeds. d. Theoretically, a particle with mass can only reach the speed of light if given infinite energy. e. Choices a), c), d) are correct.

true a and c

Explanation:

The theory of special relativity is formulated under two postulates

* that the laws of physics are the same in all inertial systems

* that the speed of light in the vacuum is constant for all systems

with these postulates the energy of a particular is

        E = K + m c²

where the last term is called energy at rest

a) True. only when m = 0 the energy of the particle is scientific energy

be False. Nothing can go faster than light

c) Right. In a material medium the speed of light depends on the measurement reference frame

d) False For a particle of finite mass the energy must be greater than the energy at rest

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.