Your television picture is created by 480 horizontal lines of pixels, arranged on a screen of total height h. Assume that your ability to resolve the lines is limited only by the Rayleigh criterion, and that the pupils of your eyes are 5.12 mm in diameter. Beyond a certain distance from the screen D, you won't be able to resolve individual lines of pixels and the TV picture will not appear pointillistic. Calculate this ratio D/h of minimum viewing distance to screen height. Assume that the average wavelength of the light coming from the screen is 537 nm.

Ratio D/h of minimum viewing distance to screen height is 16.28

Explanation:

 Given the data in the question;

Rayleigh criterion sin = 1.22 λ/D

D is diameter (5.12 mm) = 5.12 × 10⁻³

λ is wavelength ( 537 nm) = 537 × 10⁻⁹ m

so we substitute

sin = 1.22 × 537 × 10⁻⁹ / 5.12 × 10⁻³

sin  = 655.14 × 10⁻⁹ / 5.12 × 10⁻³

sin = 0.000127957

= sin⁻¹ ( 0.000127957 )

= 0.007331°

now, tan = y/D

y = h/480

so

tan = h/480 / D

h/D = 480 × tan

D/h = 1 / ( 480 × tan )

we substitute in value of

D/h = 1 / ( 480 × tan( 0.007331° ) )

D/h = 1 / ( 480 × 0.00012795 )

D/h = 1 / 0.061416

D/h = 16.28

Therefore, Ratio D/h of minimum viewing distance to screen height is 16.28

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

490 n

f=125n a=2.5m/s2