Problem 47
An example of a ferromagnetic oxide is (a) \(\mathrm{TiO}_{2}\) (b) \(\mathrm{CrO}_{2}\) (c) \(\mathrm{Mn}_{2}^{2} \mathrm{O}_{7}\) (d) \(\mathrm{Fe}_{3} \mathrm{O}_{4}^{2}\)
Problem 48
If the alignment of magnetic moments in a substance is in a compensatory way so as to give zero net magnetic moment, then the substance is said to be (a) Anti-ferromagntic (b) Diamagnetic (c) Ferrimagnetic (d) Ferromagnetic
Problem 49
Which of the following is a ferrite? (a) \(\mathrm{MgFe}_{2} \mathrm{O}_{4}\) (b) \(\mathrm{Zn}_{3} \mathrm{FeO}_{4}\) (c) \(\mathrm{AlFe}_{2} \mathrm{O}_{4}\) (d) \(\mathrm{Na}_{2} \mathrm{Fe}_{2} \mathrm{O}_{4}\)
Problem 50
An example of anti-ferroelectric substance is (a) \(\mathrm{Fe}_{3} \mathrm{O}_{4}\) (b) \(\mathrm{PbZrO}_{3}\) (c) \(\mathrm{KH}_{2} \mathrm{PO}_{4}\) (d) \(\mathrm{BaTiO}_{3}\)
Problem 52
AB ABA... represents an arrangement of layers called (a) cubic closed packing (b) fluorite closed packing (c) hexagonal closed packing (d) body-centred cubic packing
Problem 53
\(\mathrm{CaO}\) and \(\mathrm{NaCl}\) have same crystal structure and nearly the same ionic radii. If \(X\) is the lattice energy of \(\mathrm{NaCl}\), the lattice energy of \(\mathrm{CaO}\) is very nealy (a) \(\mathrm{X}\) (b) \(2 \mathrm{X}\) (c) \(4 \mathrm{X}\) (d) \(\mathrm{X} / 4\)
Problem 54
Which of the following propertes of liquids is concerned with internal resistance to its flow? (a) viscosity (b) parachore value (c) refractive index (d) surface tension
Problem 55
The unit of surface tension is (a) Joule \(\mathrm{m}^{-1}\) (b) \(\mathrm{N} \mathrm{m}^{-1}\) (c) \(\operatorname{erg} \mathrm{cm}^{-1}\) (d) none of these
Problem 56
A drop of liquid acquires a spherical shape because of (a) its tendency to maximize its surface area (b) its tendency to acquire minimum surface area (c) its viscous nature (d) none of these
Problem 57
Liquefied metals contain (a) metal anions only (b) metal cations only (c) metal kernels and mobile electrons (d) metal atoms only
