Electro-Mechanical Magic: Energy & Magnetism Unveiled

Electrical energy:
- cheaper, easily transmitted, easy to control and efficient
- generated from natural resources such as water, coal, diesel, wind, atomic energy, etc.
- Energy conversion: chemical \(\Rightarrow\) mechanical \(\Rightarrow\) electrical \(\Rightarrow\) mechanical, heat, light, etc.
Electro–mechanical energy conversion devices: convert mechanical energy into electrical energy and vice-versa
Operation of all the electrical machines such as DC/AC machines and transformers rely upon their magnetic circuits.
Magnetic circuit: Closed path followed by magnetic lines of force.
Operation of all electrical devices depends upon magnetism produced by their magnetic circuits.
Magnetic circuits of devices need to be designed carefully

Magnetic Field: region around a magnet where its poles exhibit a force of attraction or repulsion
Existence of the magnetic field at a point around the magnet can also be determined by placing a magnetic needle at that point
Although magnetic lines of force have no real existence and are purely imaginary, yet their concept is very useful to understand various magnetic effects.

direction from N-pole to the S-pole outside the magnet and from from S-pole to N-pole inside the magnet