The <span>source of fuel that is most widely used today is Natural gas. The answer is letter C. The rest of the choices do not answer the question above,</span>
Increasing the concentration of one or more reactants will often increase the rate of reaction. This occurs because a higher concentration of a reactant will lead to more collisions of that reactant in a specific time period.
Reaction rate increases with concentration, as described by the rate law and explained by collision theory. As reactant concentration increases, the frequency of collision increases. The rate of gaseous reactions increases with pressure, which is, in fact, equivalent to an increase in concentration of the gas.
Galvanometer:
its an instrument for detecting small electric currents.
Electric motor:
its an electrical machine that converts electrical energy into mechanical energy.
Answer:
7 to 4 (higher
)
5 to 3
3 to 2
4 to 2 (lower
)
Explanation:
We can use the Rydberg formula which relates the wavelength of the photon emissions to the principle quantum numbers involved in the transition:

with
final n, and
initial n
evaluating for each transition:
7 to 4 
5 to 3 
4 to 2 
3 to 2 
Note that the above formula is written for
, so lower
value obtained involves higher
.
So we should order from lower to higher 
7 to 4 (higher
)
5 to 3
3 to 2
4 to 2 (lower
)
Note: Take into account that longer wavelength involves lower energy (
).