Optical data storage cd players use an objective with na=0.45, and laser wavelength i=780nm, whereas the new blu-ray disc players use na=0.85, 1=405nm. a) what is the spot size for cd players b) what is the spot size for bluray players (use same formula asi) c) calculate the ratio of the focal spot area for the blu-ray disc player compared to cds (ie., ratio = a bluray / a cd) d) assuming that the total information on the disc scales inversely with spot area, what would this predict for the number of gigabytes for a bluray disc (cd roms are 700mb (1 mb = 1 million bytes)? e) is the spot-size reduction itself enough to explain the increased data storage of bluray discs? 1) what else could account for the difference?

explanation:

a fuel engine ( known as a gasoline engine in american english )is an internal combustion engine with spark ignition, designed to run on petrol (gasoline) and similar volatile fuels.

your answer is c! hope this : )

that would be because of both gravity and friction. so     c

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