Why there will be a change in the sole of the shoes after using many days?

See the explanation below

Explanation:

Due to the frictional force, this force acts in the opposite direction to the movement of the person's shoe. This force tends to wear the sole of any shoe. We must remember that the frictional force is defined as the product of the normal force by the coefficient of friction between surfaces.

For this case, it should be the coefficient of dynamic friction between the pavement and the material of the sole of the shoe

wavelength divides in half and speed stays the same.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia