How do step up transformers obey the law of conservation of energy?

How do step up transformers obey the law of conservation of energy?|||An ideal transformer neither generates nor consumes energy, so the power entering it will equal the power leaving it. Power can be computed by multiplying the RMS voltage by the RMS current. So, if an ideal transformer has an input voltage of (say) 100 V and an output voltage of 200 V, the current coming out will be exactly half the current going in. A real transformer is not ideal but dissipates power owing to the finite resistance of its windings and other effects, so if a real transformer steps up voltage from 100 V to 200 V, its output current will be less than half its input current.