Answer:
Explanation:
The two triangles are similar what is the length of DE
We know that frequency is an inverse value of time 
this implies that time is the inverse value of frequency 
.
Now since <em>f</em> is <em>40kHz</em><em>,</em><em> </em>we can calculate period or duration for that matter time.
Hope this helps.
r3t40
Answer:
No,it isn't concave. The correct answer is convex lens.
Explanation:
<em>A lens is a piece of transparent material bound by two surfaces of which at least one is curved. A lens bound by two spherical surfaces bulging outwards is called a bi-convex lens or simply a convex lens. A single piece of glass that curves outward and converges the light incident on it is also called a convex lens.</em>
B) Power
Because Power= Work/time
Oil spill on land and in the oceans and kills wildlife like the great barear reef
