Recent questions in Properties and Applications of Materials

The band gap of a material is $E_{g}$ and the energy of an incident photon is $E_{p}$. Optical absorption will occur in this material if,$E_{g} < E_{p}$$E_{g}>E_{p}$Elect...

Which of the following is/are polarization mechanisms in dielectric solids?Mechanical polarizationIonic polarizationElectronic polarizationThermal polarization

According to quantum free electron theory, which of the following statements is/are correct regarding the behavior of valence electrons in a metal?Valence electrons are l...

$\mathrm{Fe}$ has a density of $7.87 \mathrm{~g} . \mathrm{cm}^{-3}$, atomic mass of $55.84 \mathrm{~g} . \mathrm{mol}^{-1}$ and net magnetic moment per atom of $2.22$ Bo...

A $1 \mathrm{~cm}^{3} \mathrm{~Si}$ cube is doped with As with a concentration of $1$ atom per $10^{9} \mathrm{~Si}$ atoms. The resistance of the doped $\mathrm{Si}$ cube...

Which of the following options is/are true regarding the behaviour of a typical solar photovoltaic cell?Ideal current sourceCurrent limited voltage sourceVoltage limited ...

​​​​​The unit of measurement for magnetic dipole moment of a body is$\mathrm{A} \: \mathrm{m}^{2}$$\mathrm{A} \: \mathrm{m}^{-1}$$\mathrm{Wb} \: \mathrm{m}^{-2}$$\mathrm{...

​​​​$B$ is the magnetic flux density and $T_{c}$ is the critical temperature. The Meissner effect is represented by$\mathrm{B}=0$ at $\mathrm{T} \leq \mathrm{T}_{\mathrm{...

​For a conventional optical microscope, which of the following options regarding the resolution limit and the depth of field is/are correct?Resolution limit decreases wit...

​​​Which of the following phenomenon/phenomena contribute to intensity loss of electromagnetic radiation during transmission through a medium?Electronic absorptionRayleig...

On applying $10 \: \mathrm{V}$ across the two ends of a $100 \: \mathrm{cm}$ long copper wire, the average drift velocity (in $\mathrm{cm}\: \mathrm{s}^{-1}$ ) in the wir...

An electric field is applied on a copper plate such that the electrons are displaced by $1.1 \times 10^{-18} \mathrm{~m}$ relative to the nucleus. The electronic polariza...

Which of the following types of materials exhibit(s) positive magnetic susceptibility?ParamagneticDiamagneticFerrimagneticFerromagnetic

Which one of the following figures corresponds to the density of states $g(E)$ of a typical intrinsic semiconductor? $\text{(E represents the energy level of a charge car...

Which one of the following curves best represents the $E$ vs. $f(E)$ behavior of the hot end of a metal rod demonstrating Seebeck Effect? $\text{$( f(E)$ is the probabili...

In a typical light emitting diode (LED), which of the following type(s) of materials is/are used?Indirect bandgap semiconductor with transition metal impuritiesDirect ban...

At room temperature, the electrical conductivity and electron mobility for aluminium are $3.8 \times 10^{7}(\Omega \mathrm{m})^{-1}$ and $0.0012 \mathrm{~m}^{2}(\mathrm{~...

Q. 52 In a semiconductor, the ratio of electronic mobility to hole mobility is 10 . The density of electrons and holes are $10^{15} \mathrm{~m}^{-3}$ and $10^{16} \mathrm...

\begin{tabular}{l|l}Q. 57 & Which of the following statement(s) is/are true for an optical microscope? \\\hline& Increasing the aperture of the objective lens deteriorate...

\begin{tabular}{l|l}Q. 61 & \begin{tabular}{l}The Young's modulus of a quartz piezoelectric crystal is $100 \mathrm{GPa}$. The uniaxial \\stress required to change its po...

Q. 62 A one-dimensional nanowire has a linear electron density of $10^{8}$ electrons $\mathrm{cm}^{-1}$. The Fermi energy of the system is (in $\mathrm{eV}$ ) (rounded of...

\begin{tabular}{l|l|}\hline Q. 65 & \begin{tabular}{l}In a Raman spectroscopy experiment done at $300 \mathrm{~K}$, a Raman line is observed at \\$200 \mathrm{~cm}^{-1}(\...

Which one of the following statements is true for an intrinsic semiconductor?Electrical conductivity increases with increasing temperature and pressureElectrical conducti...

An electrochemical reaction is known to occur at $+4.50 \mathrm{~V}$ against a $\mathrm{Li}^{+} / \mathrm{Li}$ reference electrode. The potential of the same reaction aga...

The resistivity of a pure semiconductor at $298 \mathrm{~K}$ is $3000 \Omega \mathrm{m}$. Assume that the number of electrons excited $\left(n_{e}\right)$ across the band...

The third peak in the X-ray diffraction pattern of a face-centered cubic crystal is at $2 \theta$ value of $45^{\circ}$, where $2 \theta$ is the angle between the inciden...

A new glass material is developed to minimize the transmission of the light through the window with glass panel of thickness $5 \mathrm{~mm}$. The refractive index of the...