Awavelength of 486.2 nm is emitted by the hydrogen atoms in a high-voltage discharge tube. what are the (a) initial and (b) final values of the quantum number n for the energy level transition that produces this wavelength?

Along wire carrying a 4.2 a current perpendicular to the xy-plane intersects the x-axis at x=−1.7cm. a second, parallel wire carrying a 3.0 a current intersects the x-axis at x=+1.7cm. part a at what point on the x-axis is the magnetic field zero if the two currents are in the same direction? express your answer to two significant figures and include the appropriate units.