Question

Sound wave A delivers 2J of energy in 2s. Sound wave length B delivers 10J of energy in 5s. Sound wave C delivers 2mJ of energy in 1ms. Rank in order, from largest to smallest, the sound powers of Pa, Pb, Pc of these three waves.Explain. What equation would you use to determine this?

Answer 1

Answer:

$P_c=P_b>P_a$

Explanation:

E = Energy

T = Time

Power is given by the equation

$P=\frac{E}{T}$

For first case

$P_a=\frac{2}{2}\\\Rightarrow P_a=1\ W$

For second case

$P_b=\frac{10}{5}\\\Rightarrow P_b=2\ J$

For third case

$P_c=\frac{2\times 10^{-3}}{1\times 10^{-3}}\\\Rightarrow P_b=2\ J$

The rank of power would be $P_c=P_b>P_a$