Materials and Components Questions

• The v-i relation for an arc is v = 44 + . If v = 50 V, i =
• Assertion (A): Electronic polarizability increases as atoms becomes larger. Reason (R): For rare gas, ∈0(∈r - 1) E = Nae, where N is number of atoms/m3 and ae is electronic polarizability of material.
• On the basis of the type of chemical bonds, solids may be classified into
• Piezoelectricity means the slight change in dimensions of a specimen when an electric field is applied.
• Debye temperature of metals is
• A leakage capacitor can be represented by a capacitance C and resistance R in parallel C.
• A wire is carrying current I. The field intensity H at a distance r from the wire
• The materials which become polarized on the application of mechanical stress are called piezoelectric.
• If t is relaxation time and tc is average time between collisions, then in an isotropic metal
• Assertion (A): Resistivity of a perfect single crystal of a metal goes to zero as T approaches zero. Reason (R): Scattering of electrons is due to deviations from perfect periodicity of lattice.
• The merger of hole and free electron is called
• When a dielectric material is subjected to alternating field, the absorption of energy by the material from the field is given by the imaginary part of polarizability.
• If the number of atoms per unit volume of a monoatomic gas changes, the dielectric constant still remains constant.
• The residual resistivity of a binary alloy at 0 K is
• Which of the following are true for relative dielectric constant? It is dimensionless. It is equal to 1 for vacuum. It is equal to 1 for all substances.
• The elements which become superconducting at extremely low temperatures are
• The phenomenon of dielectric hysteresis occurs with
• Wood is a diamagnetic material.
• The magnetic quantum number determines the component of angular momentum along a prescribed direction.
• In an intrinsic semiconductor, at a given temperature T