The power output of a laser is measured by its wattage, the number of joules of energy it radiates per second (1 w = 1 j s-1). a 300-mw krypton laser produces a beam of red light with a wavelength of 676.4 nm (6.764×10-7 m). (a) calculate the energy carried by each photon. (b) calculate the number of photons emitted by the laser per second.

Explanation:

It is given that,

Wavelength of red light,

Power of the laser,

(a) The energy carried by each photon is given by :

(b) Let n is the number of photons emitted by the laser per second. It can be calculated as :

Hence, this is the required solution.    

5 w for 1hr = 5x60x60 joules=300x60=3000x6=18,000j as total energy conversion. efficiency of bulb needed for radiant to thermal within 18000

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