Before a person walks through burning coal, the person will make sure their feet are very wet. When they start walking on the coal, this moisture will evaporate and form a protective gas layer underneath the person's feet. You can see examples of this if you happen to drip some water on a hot stove or any very hot surface. The water will very easily glide around on top of a newly formed layer of air underneath it -- like air hockey pucks on an air hockey table. Note that when someone walks through burning coal, typically this is also done very quickly to prevent a great deal of exposure to possible harm. By walking quickly, thinking positively, and letting the water cushion you from immediate danger over a short distance, such a task is possible. You may have also heard of physics teachers demonstrating how this principle works by sticking their hand first in a bucket of water and then quickly in a bucket of boiling molten lead. In the lead, their hand is protected briefly by a layer of gas from the evaporated water (the water vapor). I'm fairly sure that there is a name for this particular layer of gas, but I'm afraid the name is beyond me at the moment. In other words, water vapor has a low heat capacity and poor thermal conduction. Very often, the coals or wood embers that are used in fire walking also have a low heat capacity. Sweat produced on the bottom of people's feet also helps form a protective water vapor. All of this together makes it possible, if moving quickly enough, to walk across hot coals without getting burned. WARNING: Do not attempt to perform any of the actions described above. You can seriously injure yourself. Answered by: Ted Pavlic, Electrical Engineering Undergrad Student, Ohio St. (citing my source)
Um tubo de raios-X é um tubo de vácuo que converte a energia elétrica em raios-X. A disponibilidade dessa fonte controlável de raios-X criou o campo da radiografia, a imagem de objetos parcialmente opacos com radiação penetrante. Em contraste com outras fontes de radiação ionizante, os raios X são produzidos apenas enquanto o tubo de raios X estiver energizado. Os tubos de raios-X também são utilizados em scanners de tomografia computadorizada, scanners de bagagem de aeroportos, cristalografia de raios-X, análise de materiais e estrutura e para inspeção industrial.
Hey there!
The correct answer to your question is: Intensity
The rate which light flows through a given area of space is referred to as its intensity. I<span>ntensity and wavelength are two factors which contribute to light energy.</span>
Thank you!
Answer:
Explanation:
Givens
The frequency is defined by
Where 
is the speed of the wave in the string and 
is its wave length.
The wave length is defined as 
Now, to find the speed, we need the tension of the wire and its linear mass density
Where 
and the tension is defined as 
Replacing this value, the speed is
Then, we replace the speed and the wave length in the first equation
Therefore, the frequency is
Answer:
We know the information about atomic size, energy, electronic configuration etc. of atom from the periodic table.
Explanation:
- Periodic table is the arrangement of elements that are arranged according to their properties and electronic configuration.
- In periodic table, on furthest right side of the periodic table, noble gases like He, Ne, Ar etc are arranged.
- The atomic number of element increases while moving from left towards right in the periodic table.
- The metallic character of element decreases as we proceed the table towards right.
- They readily accept electron to fill the valence shell hence becoming more metallic in character.
