What is the colour of the light emitted by discharge lamp filled with hydrogen when it works ?

What is the colour of the light emitted by discharge lamp filled with nitrogen when it works ?

What is the wavelength of light emitted when the electron in a hydrogen atom undergoes transmission from n=4 to n=2? ( R_(H) = 109677 cm^(-1) )

What is the energy in joules required to shift the electron of the hydrogen atom from the first Bohr orbit to the fifth Bohr orbit and what is the wavelength of the light emitted when the electron returns to the ground state? The ground state electron energy is -2.18xx10^(-11) ergs. (1erg=10^(-7)J)

Incandescent lamp, discharge lamp , C.F.L, LED lamp, arc lamp are given for observation . Answer the following questions after observing them. The colour of light depends on the gas inside the discharge lamp. Which gases are to be filled for getting white light and yellow light?

Make a Newton's disc by painting the constituent colours of white colour of white light in the same order and proportion . In which colour does the disc appear when rotated fast ?

If a bulb is lit after rejoining the parts of a broken filament , what change will occur in the intensity of the light from the lamp ? What will be the change in the power of the bulb ?

What are the advantages of using discharge lamps instead of incandescent lamps ?