Answer:
Explanation:
The energy of a photon is given by the equation , where h is the <em>Planck constant</em> and f the frequency of the photon. Thus, N photons of frequency f will give an energy of .
We also know that frequency and wavelength are related by , so we have , where c is the <em>speed of light</em>.
We will want the number of photons, so we can write
We need to know then how much energy do we have to calculate N. The equation of power is , so for the power we have and considering 1 second we can calculate the total energy, and then only consider the 4% of it which will produce light, or better said, the N photons, which means it will be .
Putting this paragraph in equations:
.
And then we can substitute everything in our equation for number of photons, in S.I. and getting the values of constants from tables:
Because the number of valence electrons of an element determines the properties and in particular the reactivity of that element.
In fact, elements of the first group (i.e. only one valence electron) have high reactivity, because they can easily give away their valence electron to atoms of other elements forming bonds. On the contrary, elements of the 8th group (noble gases) have their outermost shell completely filled with electrons, so they do not have valence electrons, and they have little or no reactivity at all.
Answer:
2 m/s²
Explanation:
the equations of motion are
S= ut +½at²
v² = u²+ 2as
v = u + at
s = (u+v)/2 × t
From the parameters given
u = 0m/s this is because it starts from rest
Distance (s) = 9m
Time (t) = 3s
Based on this the first equation would be used
s = ut + ½at²
Input values
9 = 0×3 + ½ × a x 3²
9 = 0 + 9a/2
9 = 4.5a
Divide both sides by 4.5
a = 9 / 4.5 m/s²
a = 2 m/s²
I hope this was helpful, please mark as brainliest
I honestly don't see anything above. But 'H' on a weather map usually shows the center of a high-pressure system.
Length of the sheet is given as
width of the sheet is given as
now let say its thickness is "t"
so the volume of the sheet is given as
mass of the sheet is given as
now we have
by solving above we have
so the thickness of sheet will be above