Questions

The primary agent of contact metamorphism is heat or temperature.

Dots per inch (DPI, or dpi) is a measure of spatial printing or video or image scanner dot density, in particular the number of individual dots that can be placed in a line within the span of 1 inch (2.54 cm).

Exchange Traded Funds (ETFs) are a relatively new phenomenon and are gaining popularity rapidly. This post outlines the key features of an ETF.

ETFs are like mutual funds because they hold an underlying asset like stocks, debt, commodities future contracts etc. If you are new to the concept of an ETF, think of it as a mutual fund, and build your understanding from thereon. An example of an ETF is the SBI Gold ETF, which holds physical gold as its underlying asset.

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. 

Conduction is the movement of heat through a substance by the collision of molecules. It occurs when two object at different temperatures are in contact with each other. Heat flows from the warmer to the cooler object until they are both at the same temperature.

Wavelength of a wave can be measured with the distance between two nearest crest and crest or nearest troughs. It is measured as armstrong units.