Suppose that two identical stars (they have the same total light output) are located so that star a is at a distance of 5 pc and star b is at a distance of 25 pc from earth. how will star b appear, compared with star a?

star B will appear 1/25 = 0.04 times compared to star A

star b will look smaller from star A

Explanation:

star A is at a distance of 5 pc

star B is at a distance of 25 pc

How will star B appear, compared with star A?

the inverse square law of light for apparent brigthness, b =

b= L/(4πd²)

where, L is the luminiosity = light output

d = distance

L₁/(4πd₁²) = L₂/(4πd₂²)

since L, is constant

d₁² = d₂²

5² = 25²

[5/25]² = [1/5]² = 1/25

star B will appear 1/25 = 0.04 times compared to star A

star b will look smaller from star A

as a general rule, scissors have blades less than 6 in (15 cm) long and usually have handles with finger holes of the same size. shears have blades scissors used to cut hair or fabric must be much sharper

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