Answer: 4 is the subscript in .
Explanation:
We know that,
Subscript: The number of atom present in a given compound.
In , 4 represents the number of chlorine atom in 1 mole of Silicon tetra chloride.
Coefficient: Number of atom which is used in reaction.
For example: In , 3 is the coefficient of silicon tetra chloride.
A Product : In the balance equation, right hand side is called product.
A reactant : In the balance equation, left hand side is called reactant.
For example: the balance equation is
In this equation, is the reactants and
is products.
Hence, 4 is the subscript in .
Answer:
C is halved
Explanation:
The frequency and the wavelength of a wave are related by the equation:
where
v is the speed of the wave
f is the frequency
is the wavelength
From the equation above, we see that for a given wave, if the wave is travelling in the same medium (and so, its speed is not changing), then the frequency and the wavelength are inversely proportional to each other.
Therefore, if the frequency doubles, the wavelength will halve in order to keep the speed constant:
Answer: The weight of the air displaced by the balloon is less than the volume of the balloon.
Explanation:
A hot air balloon is a cloth wrap that contains several thousand cubic meters of air inside (a large volume of air). The burner heats the liquid propane to a gaseous state to generate a huge flame, which can reach more than 3 meters, thus heating the air mass inside the balloon. In this way,<u> its density is modified with respect to the air that surrounds it</u>, because the hot air is lighter than the outside air (less dense), causing the balloon to rise and float.
Now, if we know that the density of a body is directly proportional to its mass
and inversely proportional to its volume
:
We can deduce that <u>by increasing the volume of the body, its density will decrease.</u>
This is proof of <em><u>Archimedes' Principle</u></em>:
<em>A body totally or partially immersed in a fluid at rest, experiences a vertical upward thrust equal to the mass weight of the body volume that is displaced.</em>
In this case the fluid is the air outside. So, the warm air inside the balloon, being less dense, will weigh less than the outside air and therefore will receive an upward pushing force or thrust that will make the balloon ascend.