<span>Not all elements have strong visible spectra in a flame</span>
C. both a and b
If a light bulb can last longer with the same amount of energy it is given, that means it can use less energy to do the same job compared to one that does not last longer with the same amount of energy it is given. It is much like how a more fuel efficient car will be able to go farther on the same tank of gas, but if you pair it with a car that doesn't have as great of an mpg, when they go the same distance, the car with the greater mpg spends less fuel.
If you don't have to use the energy when you aren't utilizing it, then you can conserve the energy for when you do need it.
To answer this problem, we must make assumptions for simplicity. The first assumption is that, the system only consist of these 3 gases. The second assumption is that, these gases behave ideally. Thus, from Dalton's Law of Partial Pressure, the total pressure is simply the sum of their individual partial pressures.
Total pressure = 2.5 + 0.8 + 3.4 = <em>6.7 atm</em>
Sounds travels most rapidly in solid objects, especially those that are dense. These objects have closely packed atoms, and energy that is traveling in vibrations (the sound) can easily pass between the touching atoms.