2 example of partially permeable please I'm in hurry please

The term gas is limited to those substances that exist in the gaseous state at

What is the equation for calculating rf values

How long could you survive without electricity? what parts of your life would be affected by loss of electricity? should you prepare for an electricity outage, and if so, how would you prepare? what backup system could your family or community install to generate limited amounts of electricity during an outage? how does this system create an electric force field and generate electric current?