If a nuclear device has been detonated near your area, and you are considering the type of protective shielding you might need, you would use lead shielding for protection against which type of radiation?

Gamma rays

Explanation:

If a nuclear device is detonated near your area it emits Gamma Rays.

Gamma rays are one of the harmful rays which have a very high penetrating power.                    

Gamma rays can damage the cells of the human body.

Also gamma ray penetration can cause cancer.              

Gamma rays affect unborn baby very adversely.

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.

k2s for potassium sulphide