Materials and Components Questions

• Assertion (A): Ferroelectric materials have spontaneous polarization. Reason (R): Above curie temperature, ∈ = for ferro-electric materials.
• Which capacitor-store higher amount of energy?
• If the temperature of an extrinsic semiconductor is increased so that the intrinsic carrier concentration is doubled, then
• Assertion (A): Magnetic susceptibility of diamagnetic materials is much less than that of paramagnetic materials. Reason (R): For diamagnetic as well as paramagnetic materials, μr is nearly equal to 1.
• Which element exhibits the property of inertia?
• In a true valence crystal, the bonding between the atoms is accomplished by the sharing of valence electrons.
• The units of μ0 and μr are
• Assertion (A): If E is available energy state eV and EF is Fermi level, then probability of energy state E being occupied = 0.5. Reason (R): .
• Two materials having temperature coefficients of 0.004 and 0.0004 respectively are joined in series. The overall temperature coefficient is likely to be
• If the diameter of a wire is doubled, its current carrying capacity becomes
• As the temperature of a pure silicon specimen is increased
• When a material becomes a superconductor, its resistivity becomes
• In metals the thermal conductivity K and electrical conductivity σ are related as (K/σT) = L, L is known as
• In metals, the average drift velocity of electron per unit field is called mobility.
• Silicon and germanium atoms combine orderly into array of atoms located in repetitive geometric pattern. This pattern is called
• Dielectric constant of transformer oil is about
• In carbon resistor colour code, the third band is red. It indicates
• Assertion (A): In many materials, dielectric polarization causes mechanical distortion. Reason (R): If dielectric polarization causes mechanical distortion then mechanical distortion must cause dielectric polarization.
• Consider the following statement If an electric field is applied to an n type semiconductor bar, the electrons and holes move in opposite directions due to their opposite charges. The net currents is both due to electrons and holes with electrons as majority carriers sum of hole and electron currents difference between electron and hole currents. Which of above statements are correct?
• Assertion (A): ∈r can be determined experimentally by measuring the capacitance of a parallel plate capacitor with and without the dielectric. Reason (R): Capacitance of a parallel plate capacitor = .