The intensity of the sound wave reaching your ear from a car radio 140 m away from you is 0.050 W/m2. The car drives toward you, so that the distance between you and the radio has decreased to one-fourth of its original value. Determine the new intensity of the sound reaching your ear.

intensity (I2) = 0.8W/m²

Explanation: The relationship between the intensity of sound wave obeys the inverse square law, that's the intensity (I) is inversely proportional to square of distance (r).

I α r², I= kr²

I1 * (r1)² = I2 * (r2) ²

From the question,

I1 = 0.050W/m², r1 = 140m, I2 =?, r2= 1/4 * 140 = 35m.

By substituting the parameters, we have that

0.05 * (140)² = I2 * (35)²

0.05 * 19600 = I2 * 1225

980 = I2 * 1225

I2 = 980/1225

I2 = 0.8W/m²

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

d. platinum would have the greatest temperature increase because it has the lowest specific heat.