Questions

Strength of concrete increases with increase in water cement ratio as the strength of the cement is directly proportional to water cement ratio.

Along any transmission path from a given source to a given destination, a group of virtual circuits can be grouped together into what is called path.

The resistivity of wire or the metal conductor is depend on the number density of free electrons in the conductor. so its mainly depends on nature of the material

Resistivity :

Resistivity is a measure of the resistance to the flow of electrons. 

Conductivity :

Conductivity is just the inverse of resistivity, σ = 1/ρ, where σ is conductivity and ρ is resistivity.

Example:

Think of a pipe and water, the bigger the pipe, the easier water can flow and thus the lower the resistance. 

Refractive Index of glass with respect to water can be calculated by 

(Refractive Index of glass with respect to air) × (1/Refractive Index of water with respect to air)

We know that,

Refractive Index of glass with respect to air = 4/3

Refractive index of water with respect to air = 3/2

Hence, Refractive Index of glass with respect to water = (4/3) x (2/3) = 8/9.

Self pollination occurs in the flowers when the pollen grains of the flower falls on the stigma of the same due to wind or insects like moths and bees. This lead to the inbreeding.