Pressure can be defined as the force acting on a perpendicular surface per unit area.
Force exerted by a man of mass 100 kg wearing snow shoes = m.a
Where m = mass of the man = 100 kg
a = acceleration due to gravity= 9.8 
Force exerted by the man of mass 100 kg = 
Force exerted by woman of mass 60 kg = 
Force exerted by 100 kg man is greater than that exerted as 60 kg woman. The area on which this force is acting determines the pressure. Pressure is inversely proportional to the area on which the force acts. Therefore, the pressure exerted by 100 kg man wearing snow shoes is less than the pressure exerted by a 60 kg woman woman wearing high heels as the force acts over a larger area when the man wears snow shoes when compared to the force exerted over a smaller area in case of the woman wearing high heels.
18)
a. Ra
d. Ag
19)
a. C
b. Br
c. Mg
20)
a. S
b. Br
c. O
Sorry wasn’t sure about some of them in #18
Hope the notes are helpful.
Answer:
91.1835 nm
Explanation:
Given that the ionization energy of the oxygen molecule = 1314 kJ/mol
It means that
1 mole of oxygen molecules can be ionized by the energy = 1314 kJ = 1314000 J
1 mole of molecules contains 6.022 × 10²³ atoms
So,
6.022 × 10²³ atoms of oxygen molecules can be ionized by the energy = 1314000 J
1 atom require
of energy
Energy = 
Also
Where,
h is Plank's constant having value
c is the speed of light having value 
is the wavelength
So,
Also,
So, wavelength = 91.1835 nm
It could be used as a buffer, since it is not a conductor. Hope this helps!!!