Answer:
The correct answer is (a), heating and soaking at a temperature above the austenitizing level followed by rapid cooling.
Explanation:
Tempering is a heat treatment that is performed to change microstructure of steel <em>and increase it's hardness.</em>
It is done by heating above the austenitizing level, because for this heat treatment it's necesary to heat the steel to get <em>austenite structure</em> that is the <em>alotropic form of gamma iron.</em>
The procedure of tempering, continues with rapid cooling, because this way you get the microstructure with the best hardness properties, that is <em>martensite.</em>
B i believe not really sure but that math i did seems about right
The amount of NOx emission produced by a household is required.
The total amount of NOx the household is responsible for is 91.06 kg.
1 car produces 11 kg of NOx per year.
Natural gas burning produces 4.3 g of NOx per therm.
Electric power plant produces 7.1 g of NOx per kwh.
2 cars will produce 
of NOx.
1200 therms of natural gas will produce 
9000 kWh will produce 
Converting all to kg and finding the total amount
The total amount of NOx the household is responsible for is 91.06 kg.
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Answer:
Power is associated by many people with electricity. Knowing that power is the rate of energy use or energy conversion, what is the expression for electric power? Power transmission lines might come to mind.
