It is possible to derive the age of the universe given the value of the hubble constant and the distance to a galaxy, again with the assumption that the value of the hubble constant has not changed since the big bang. consider a galaxy at a distance of 400 million light-years receding from us at a velocity, v. if the hubble constant is 20 km/s per million light-years, what is its velocity? how long ago was that galaxy right next door to our own galaxy if it has always been receding at its present rate? express your answer in years. since the universe began when all galaxies were very close together, this number is a rough estimate for the age of the universe.

what is the actual question though?

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

i would say