Which of the following is true regarding the properties of light? a. light needs a medium to propagate through a vacuum. b. light can only travel in a straight line. c. light is not able to display interference or diffraction. d. light has a dual nature and acts like both a wave and a particle

Option (d) is correct.

Light has a dual nature and acts like both a wave and a particle. This theory was given by Einstein. There are some properties which can be explained only if we consider light as a wave like interference, diffraction , polarization etc . Some other properties like black body radiation, photoelectric effect can be only explained if we consider light as a particle. So, we say that light has dual nature. Light is made of packets of energy called as photons.

D. Light has a dual nature and acts like both a wave and a particle

Explanation:

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.

float.

archimedes' principle

denser than water sinks in water.

denser than mercury would sink in it