A plane transmission grating is ruled with 4500 slits/cm . Assume normal incidence. The α and β lines emitted by atomic hydrogen have wavelengths of 656 nm and 486 nm , respectively. Compute the angular separation in degrees between these lines in the first-order spectrum and second-order spectrum.

f=ma newton

f=100x2.5=250n

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

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