What inference can be drawn from the following evidence? Specific atoms of carbon from a dead animal can be traced to the leaves of a living plant. A. Carbon exists only in animals
B. Carbon is moved throughout many different objects, but the total amount of carbon doesn’t change.
C. The animal must be eating the plant for food
D. Carbon is found more in plants than it is in animals.

C

Explanation: Trust

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.

electric field is a function of 1/r^2

yes, the force per unit charge for a point charge is inverse square law.