Answer:
(a) Ferromagnet
Explanation:
Ferromagnetism is defined as the property by which certain magnets form the permanent magnets.
It is tone of the strong magnetism and it is common phenomenon of magnet in the everyday life of magnetism.
Permanent magnets are made up of ferromagnetic material, in this if the magnetic field is applied then this material is magnetized but do not losses its magnetic property after removal of external magnetic field.
<span>You cant change the curve of a graph with out changing the equation</span>
The first law of thermodynamics is expresses by
D. ΔU=Q-W
which means change in internal energy of system = Heat added to system minus work done by the system
All are expressed in Joules.
This law is based on principle of conservation of energy.