Spectral lines from galaxy b are redshifted from their rest wavelengths twice as much as the spectral lines from galaxy a. according to hubble's law, what can you say about their approximate relative distances?
a. galaxy a is twice as far as galaxy b.
b. galaxy b is four times as far as galaxy a.
c. galaxy a is four times as far as galaxy b.
d. galaxy b is twice as far as galaxy a.
e. not enough information to say

a. Galaxy A is twice as far as Galaxy B.

Explanation:

The correct answer is  Galaxy A is twice as far as Galaxy B. that is option a.

This can be explained as per the Hubble's law, The more the distance between two galaxies the faster they are moving away from each other. It is given that red shift of galaxy A is twice as that of B. This means that A is twice as far B.

Note: When an object moves away from us the light is shifted to the red end of the spectrum.

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