Answer:
The Balmer series refers to the spectral lines of hydrogen, associated to the emission of photons when an electron in the hydrogen atom jumps from a level
to the level
.
The wavelength associated to each spectral line of the Balmer series is given by:

where
is the Rydberg constant for hydrogen, and where
is the initial level of the electron that jumps to the level n = 2.
The first few spectral lines associated to this series are withing the visible part of the electromagnetic spectrum, and their wavelengths are:
656 nm (red, corresponding to the transition
)
486 nm (green,
)
434 nm (blue,
)
410 nm (violet,
)
All the following lines lie in the ultraviolet part of the spectrum. The limit of the Balmer series, corresponding to the transition
, is at 364.6 nm.
Communication circuit <em>(D)</em> is becoming more common in residential electrical design and construction.
LAN Ethernet cables, outlets, and even hubs and bridges, are being built into the walls of new homes, along with the usual electrical outlet wiring, to give the owner the networking infrastructure and internet access that everybody needs now ... without stringing a mess of cables on the floor and through doors all over the house.
Refraction is the bending of a wave disturbance as it passes at an angle from one medium into another