Questions

The given statement "All bones stop growing by the end of adolescence" is a FALSE statement.

In Chennai, Tamil Nadu place India's first HIV case reported in 1986 amongst the female sex workers.

Tractor was the single most important invention to farmers.

Cotton Gin was invented by Eli Whitney in 1793, which is used to separate cotton seeds from cotton fiber.

Hence, it was an important invention because it dramatically reduced the amount of time it took to separate cotton seeds from cotton fiber.

Hypnosis is a state of human consciousness involving focused attention, reduced peripheral awareness, and an enhanced capacity to respond to suggestion.

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. 

From the given circuit,

The resistors R1 and R2 are in parallel connection and R3 is in series with R1 & R2

The equivalent resistance of R1 and R2 is

Req = (12 × 4)/(12 + 4) = 3 Ω.

Adding R3 in series with the pair gives

R = Req + 9

R = 3 + 9

R = 12 Ω.