Which of the following series of transitions in the spectrum of hydrogen atom fall in visible region?

The Lyman series of hydrogen spectrum lies in which region

A body of mass 10 mg is moving with a velocity of 100 ms$$^{-1}$$. The wavelength of de-Broglie wave associated with it would be

($$h=6.63\times10^{-34}$$ Js)

Mg$$^{2+}$$ is isoelectronic with