There is no certain time on how long it takes. Because the factors will always be different and the factors heavily affect the evaporation time. Some factors include: humidity, heat, how the sun is visible (whether clouds are covering it or not)
Answer:
i/f = i/o + i/i f = focal, o = object, i = image
1 / i = 1 / f - 1 / o = (o - f) / o f
i = o * f / ( o - f) image distance
i = 12.5 * 22 / (12.5 - 22) = -28.9 cm
Image is real
Image is 28.9 cm to left of lens
M = - i / o = = 28.9 / 12.5 = 2.3 magnification (convex lens)
Answer:
To find the acceleration of the object we have to apply Newton second law of motion that is F = mass × acceleration.
Explanation:
Given ,
F = 130N
M = 24kg
A = ?
F = m× a
then ,
130N = 24kg ×a
a = 130/24 = 5 m/s.
Answer:
Option b. Effective nuclear charge increases as we move to the right across a row in the periodic table
Explanation:
The <em>effective nuclear charge </em>is a measure of how strong the protons in the nucleus of an atom attract the outermost electrons of such atom.
The <em>effective nuclear charge</em> is the net positive charge experienced by valence electrons and is calculated (as an approximation) by the equation: Zeff = Z – S, where Z is the atomic number and S is the number of shielding electrons.
The shielding electrons are those electrons in between the interesting electrons and the nucleus of the atom.
Since the shielding electrons are closer to the nucleus, they repel the outermost electrons and so cancel some of the attraction exerted by the positive charge of the nucleus, meaning that the outermost electrons feel less the efect of attraction of the protons. That is why in the equation of Zeff, the shielding electrons (S) subtract the total from the atomic number Z.
The <em>effective nuclear charge</em>, then, is responsible for some properties and trends in the periodic table. Here, you can see how this explains the trend of the atomic radius (size of the atom) accross a row in the periodic table.
- As the<em> effective nuclear charge</em> is larger, in a same row of the periodic table, the shielding effect is lower, the outermost electrons are more strongly attracted by the nucleus, and the size of the atoms decrease. That is why as we move to the right in the periodic table, the size of the atoms decrease.
