3 vowels, 3 places ! remaining !
Total ! 4!

For a dia-magnetic substance, is negative and Therefore, the variation is represented by . As magnetisation is small, is better choice.

Young’s modulus

Since for same material Young’s modulus is same,

or
or

Area of hysterisis loop gives the energy loss in the process of stretching and unstretching of rubber band and this loss will appear in the form of heating

Work done =

= 4

If coefficient of volume expansion is and rise in temperature is then
Volume elasticity

Iron is a ferromagnetic substance and ferromagnetic substance obeys Curie-Weiss law above its Curie temperature.

For permanent magnet we prefer a material with high retentivity (so as to make a stronger magnet) and high coercivity (so that magnetization may not be wiped out easily). For electromagnet we prefer high saturated magnetism, low coercivity and least possible area of hysteresis loop so that electromagnet develops high magnetization, is easily demagnetized and energy loss in a magnetization cycle is least. Therefore, Pis suitable for making permanent magnet and Q for making electromagnet.

Diamagnetic materials have negative susceptibility. Thus, (c) is wrongly stated.

The materials for a permanent magnet should have high retentivity (so that the magnet is strong) and high coercivity (so that the magnetism is not wiped out by stray magnetic fields). As the material in this case is never put to cyclic changes of magnetization, hence hysteresis is immaterial.

Therefore,


Or