Faraday's law of electro magnetic induction

Faraday discovered that when he moved a magnet near a wire , a voltage is generated across it . When the magnet was held stationary , that is if we don't move the magnet then no voltage is generated . This means voltage exists only when the magnet was moving . We call this voltage as " INDUCED EMF ( E ) " . This also means voltage existed because of magnetic field . This field has both horizontal and vertical components. But only vertical component contributes to the generation of electricity . Let theta be the angle between the normal and vertical component of magnetic field . Then , Faraday's law can be written as , Induced voltage E is proportional to the rate of change of magnetic flux ' theta ' . through the area of loop of conductor . This voltage is denoted with the negative sign to indicate that the voltage opposes the rate of change of magnetic flux .