Match the symbols used in electric circuit diagrams to their functions

Hydrogen atoms are excited by a laser to the =4n=4 state and then allowed to emit. what is the maximum number of distinct emission spectral lines (lines of different wavelengths) that can be observed from this system? 8 6 2 7 4 5 1 3 calculate the wavelength of the 4⟶14⟶1 transition. =λ=

To a of 4 x hz is 1. 0. mm nm nm

Awave has a wavelength of 7 mm and a frequency of 19 hertz. what is its speed?