Atrain at rest emits a sound at a frequency of 1045 hz. an observer in a car travels away from the sound source at a speed of 22.4 m/s. what is the frequency heard by the observer? assume the speed of sound in air to be 344 m/s. answer in units of hz

Explanation:

Let be the speed of sound in medium.

Let be the speed of the source.

Let be the speed of the observer.

Let be the frequency emitted by the source when the source is in rest.

Let be the frequency observed by the observer.

When the observer is moving away and the source is at rest,

Given,

no

sodium is solid at rt

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