I just need points to ask my own question.
Answer:
Approximately 
.
Explanation:
In that 
, this sound wave travelled from the surface of the lake to the bottom, got reflected, and travelled back from the bottom to the surface. The sound wave travelled from the surface to the bottom (without bouncing back) in only 
that much time. In other words, it took only 
for the sound wave to travel from the surface to the bottom of the lake.
The speed 
of sound in cold water (
, 
) is approximately 
.
In 
, that sound wave would have travelled a distance of:
.
Therefore, the depth of the lake is approximately .
Answer:
Substances that cannot be broken down into other substances are called elements.
Explanation:
Elements are pure substances that cannot be broken down into other elements through any non-nuclear means. For example: hydrogen, helium, lithium, beryllium, boron, and carbon.
A list of the elements can be found in a periodic table.
Answer:
a-
50°C whn converted into K - 323 K
