Bright Line Emission Spectrum: As the excited electron returns to ground state (it's lower energy level) the energy it originally absorbed is released as discrete lines of light.
The correct answer is option D, that is, a storage battery is charged using an electric current.
The transformation of one form of energy into another, generally to transform the energy into more useful kind is known as energy conversion. The energy can neither be created nor be destroyed, it can only be transformed. The different forms of energy comprise light, heat, mechanical, electrical, sound, nuclear, and sound.
In the given question, the charging of a storage battery using electric current is an example of electrical energy being converted into chemical energy.
Molarity (M) is the concentration of a solution expressed as the number of moles of solute per liter of solution: Molarity (M) = moles solute. liters solution.