Answer:
cell pohnes convert sound waves into radio waves
electromagnetic waves used in cellphone communications are called: radio waves
To send out a radio signal far and wide.. it is called: broadcast
Explanation:
Answer:
Explanation:
The relationship between the refractive index and the critical angle is given as follows:
where,
η = refractive index = 1.67
θc = critical angle =?
Therefore,
Answer:
Radio waves
Explanation:
The electromagnetic spectrum includes all different types of waves, which are usually classified depending on their frequency. Ordering them from the highest frequency to the lowest frequency, they are:
- Gamma rays
- X-rays
- Ultraviolet
- Visible light
- Infrared radiation
- Microwaves
- Radio waves
Radio waves are the electromagnetic waves with lowest frequency, their frequency is lower than 300 GHz (
) and therefore they are the electromagnetic waves with lowest energy (in fact, the energy of an electromagnetic wave is proportional to its frequency). They are generally used for radio and telecommunications since this type of waves can travel up to long distances.
<span>
The purpose of a gasoline car engine is to convert gasoline into motion
so that your car can move. Currently the easiest way to create motion
from gasoline is to burn the gasoline inside an engine.
Therefore, a car engine is an internal combustion engine -- combustion takes place internally.
There is such a thing as an external combustion engine. A steam engine
in old-fashioned trains and steam boats is the best example of an
external combustion engine. The fuel (coal, wood, oil, whatever) in a
steam engine burns outside the engine to create steam, and the steam
creates motion inside the engine. Internal combustion is a lot more
efficient (takes less fuel per mile) than external combustion, plus an
internal combustion engine is a lot smaller than an equivalent external
combustion engine. This explains why we don't see any cars using steam
engines.
To understand the basic idea behind how a reciprocating internal
combustion engine works, it is helpful to have a good mental image of
how "internal combustion" works.
One good example is an old Revolutionary War cannon. You have probably
seen these in movies, where the soldiers load the cannon with gun powder
and a cannon ball and light it. That is internal combustion, but it is
hard to imagine that having anything to do with engines.
A potato cannon uses the basic principle behind any reciprocating
internal combustion engine: If you put a tiny amount of high-energy fuel
(like gasoline) in a small, enclosed space and ignite it, an incredible
amount of energy is released in the form of expanding gas. You can use
that energy to propel a potato 500 feet. In this case, the energy is
translated into potato motion. You can also use it for more interesting
purposes. For example, if you can create a cycle that allows you to set
off explosions like this hundreds of times per minute, and if you can
harness that energy in a useful way, what you have is the core of a car
engine! </span>
