B Ik it all just know who they’ll you
Option B & Option D is your correct answers.
'cause here, atom has eight electrons in it's valence shell, so it means it has stable structure which falls in group 18
Hope this helps!
The top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it. Because the contact between the bolt and the pliers working surface is less.
<h3>What is mechanical advantage ?</h3>
Mechanical advantage is a measure of the ratio of output force to input force in a system, it is used to obtained efficiency of the given mechanical machine.
The efficiency to open the stubborn bolt depends upon the contact between the working surface of the pliers and the bolt.
The contact between the bolt and the top pair of pliers working surface is less. Its mechanical advantage is less.
Hence, the top pair of pliers failed to loosen a stubborn bolt, but the bottom pair successfully removed it.
To learn more about the mechanical advantage, refer to the link;
brainly.com/question/7638820
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Answer:
Ф = 2.179 eV
Explanation:
This exercise has electrons ejected from a metal, which is why it is an exercise on the photoelectric effect, which is explained assuming the existence of energy quanta called photons that behave like particles.
E = K + Ф
the energy of the photons is given by the Planck relation
E = h f
we substitute
h f = K + Ф
Ф= hf - K
the speed of light is related to wavelength and frequency
c = λ f
f = c /λ
Φ = 
let's reduce the energy to the SI system
K = 0.890 eV (1.6 10⁻¹⁹ J / 1eV) = 1.424 10⁻¹⁹ J
calculate
Ф = 6.63 10⁻³⁴ 3 10⁸/405 10⁻⁹ -1.424 10⁻¹⁹
Ф = 4.911 10⁻¹⁹ - 1.424 10⁻¹⁹
Ф = 3.4571 10⁻¹⁹ J
we reduce to eV
Ф = 3.4871 10⁻¹⁹ J (1 eV / 1.6 10⁻¹⁹ J)
Ф = 2.179 eV
