Voltage and current remain constant as in DC circuits. Energy is not lost in a transformer. A step-up transformer gives you something more for less input. Transformers can be used to change DC voltages. Electrical companies supply the electrons for your household current.
Light can be a particle at one point in time and a wave at another point in time.
Particles can't have wave properties. Waves can't have particle properties. The position of a particle always can be exactly known. A photon is a particle with a wave inside. Photons of higher frequency are bigger than photons of lower frequency.