A boy hears the echo of his own voice from a distance hill after 0.8 seconds. If the speed of sound in air is 340m/s, calculate the distance of the hill from the boy.

the distance is going be 136 since velocity of sound waves =to 2* the distance(meter) all time taken(in second)

The required distance = 340 × 0.8 m.

= 272m

Explanation:

So the only thing you need here is :

distance = speed × time

So the speed of the wave here is 340m/s.

Time taken = 0.8s

So, By using the speed-distance formula here,

The required distance = 340 × 0.8 m.

= 272m.

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