How is an emission spectrum of an element generated?

-when an electron in an atom is excited to a higher energy state.
-when an electron in an atom is in the excited state.
-when an electron in an atom returns from an excited state to a lower energy state.
-when an electron in an atom is in the ground state.

Complete the following reactions using word and balanced equations including states. dilute phosphoric acid is added with a calcium hydroxide solution.

Percent ionization for a weak acid (ha) is determined by the following formula: percent ionization=[ha] ionized[ha] initial×100%for strong acids, ionization is nearly complete (100%) at most concentrations. however, for weak acids, the percent ionization changes significantly with concentration. the more diluted the acid is, the greater percent ionization. a certain weak acid, ha, has a ka value of 9.4×10? 7.part acalculate the percent ionization of ha in a 0.10 m solution. part bcalculate the percent ionization of ha in a 0.010 m solution

Which is the best metal to use in an alloy to increase its electrical conductivity?