A physical quantity is something which can be measured and whose measurement is necessary because all the laws of physics are given in terms of these physical quantities. The examples of physical quantity are mass, length, time, temperature, electric current, velocity , acceleration, force, work, weight,power, energy etc.
There are some quantities which cannot be measured and hence are not classified as physical quantities , for example, love, honesty, hatred etc
Thus a physical quantity is a quantity which can be measured.
Electrons are a stable sub atomic particle that has a negative charge and is found in all atoms and is the main carrier of electricity through solids.
In a metal, some of the electrons can escape from the atoms and are free to move around inside the metal. These electrons are referred to as 'conduction electrons'.
<span>A current is a flow of charge. In metal a current is the flow of the conduction electrons through the metal. This can occur when connected to battery for example: The battery pumps the conduction electrons around the circuit. </span>
Define
v = volume of a drop per second, cm³/s
The time taken to fill 200 cm³ is 1 hour.
Let V = 200 cm³, the filled volume.
Let t = 1 h = 3600 s, the time required to fill the volume.
Therefore,
The average volume of a single drop is approximately 0.0556 cm³.
Answer: 0.0556 cm³
At STP, 1 mole of an ideal gas occupies a volume of about 22.4 L. So if <em>n</em> is the number of moles of this gas, then
<em>n</em> / (19.2 L) = (1 mole) / (22.4 L) ==> <em>n</em> = (19.2 L•mole) / (22.4 L) ≈ 0.857 mol
If the sample has a mass of 12.0 g, then its molecular weight is
(12.0 g) / <em>n</em> ≈ 14.0 g/mol
