The answer is C.
Ionic compounds are those that bring together anions and cations bonded together by ionic bonds. The electrostatic forces of the different charges are significant in the bonds that make them strong hence require high energy to break them (high melting point). Due to the regular structure of ionic compound that tend to form lattices in solid form, when struck, they shatter along the lines of weakness of the lattice.
Answer:
Pressure on both feet will be
Explanation:
Weight of the person F = 500 N
Area of foot print 
Area of both the foot 
We have to find pressure on both the feet
Pressure is equal to ratio of force and area
So pressure 

So the pressure on both feet will be
when person stands on both feet.
X - rays are highly penetrating electromagnetic radiations that are formed when the cathode rays strikes a dense metal.
It has many characteristics such as :
- travels with the speed of light.
The frequency of this wave is 3