If two 50-N weights are attached to the opposite ends of a spring scale, and allowed to hang off the sides of the table upon which the spring scale rests, what is the tension
force on the spring scale in Newtons? (what is the reading on the scale?)
O a. Tension = 50 N
O b. Tension = 200 N
O c. Tension = 100 N
O d. Tension = ON

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.