Materials and Components Questions

• The number of valence electrons in trivalent impurity is
• Assertion (A): In a conductor, current density remains constant in time as long as E is constant. Reason (R): In a conductor, J = σE.
• The most important primary force of attraction in the formation of solids is
• The units of polarization of dielectric are
• Antiferromagnetic materials do not have permanent dipoles.
• Silicon and germanium are elements in the
• An atom of polarizability a is placed in a homogeneous electric field E. The energy stored in polarized atom is
• A capacitor can be represented by a capacitance and resistance in parallel. For a good capacitor, this parallel resistance should be
• When a potential is applied across an intrinsic semiconductor, holes flow
• ∈0 has no other physical meaning than that of a fundamental conversion factor.
• n type semiconductors
• Assertion (A): Acceptor extrinsic semiconductor has higher conductivity than intrinsic semiconductor. Reason (R): Addition of p-type impurity produces an allowable discrete energy level just above valence band.
• In the wave mechanical theory, the maximum of the charge distribution in the ground state occurs for a distance from the nucleus equal to
• The colour code on a carbon resistor is brown-black-red-gold. The value of resistance is
• Tesla is a unit of
• The number of protons in germanium atom is
• A magnet does not attract
• At 0 K, silicon and germanium behave like monoatomic crystals.
• Two coaxial metallic cylinders have radii R1 and R2. The space between them is filled with a dielectric having dielectric constant ∈r. The capacitance per metre length is
• Hysteresis curve is associated with motion of domain walls.