In an \(\mathrm{n\text{-}}\)type silicon, which of the following statement is true:

Carbon, silicon, and germanium have four valence electrons each. These are characterized by valence and conduction bands separated by the energy bandgap respectively equal to \((E_g)_C, (E_g)_{Si}~\text{and}~(E_g)_{Ge}\). Which of the following statements is true?

In an unbiased \(\mathrm{p\text-n}\) junction, holes diffuse from the \(\mathrm{p\text-}\)region to the  \(\mathrm{n\text-}\)region because:

In a half-wave rectification, what is the output frequency if the input frequency is \(50\) Hz?
1. \(50~\text{Hz}\)
2. \(100~\text{Hz}\)
3. \(25~\text{Hz}\)
4. \(60~\text{Hz}\)

A p-n photodiode is fabricated from a semiconductor with a bandgap of \(2.8\) eV. The energy of the incident photon with a wavelength of \(6000\) nm is:
1. \(0.207\) eV
2. \(0.270\) eV
3. \(0.027\) eV
4. \(0.072\) eV

The number of silicon atoms per m³ is 5 × 10²⁸. This is doped simultaneously with 5 × 10²² atoms per m³ of Arsenic and 5 × 10²⁰ per m³ atoms of Indium. The number of holes is: (Given that $n_i=1.5\times {10}^{16} m^{-3}$)

1. \(4.51\times 10^{9}\)
2. \(4.99\times 10^{22}\)
3. \(1.56\times 10^{22}\)
4. \(3.33\times 10^{23}\)

In an intrinsic semiconductor, the energy gap Eg is \(1.2~\text{eV}\). Its hole mobility is much smaller than electron mobility and independent of temperature. What is the ratio between conductivity at \(600~\text{K}\) and that at \(300~\text{K}\)? Assume that the temperature dependence of intrinsic carrier concentration \(n_{i}\) is given by
\(n_{i} = n_{0} exp \left[\frac{- E_{g}}{2 k_{B} T}\right]  \), where \(n_0\) is the constant.
1. \(1.01\times10^6:1\)
2. \(1.09\times10^5:1\)
3. \(1:1\)
4. \(1:2\)

Which statement is true for the given circuit:

1. (a) is OR gate and (b) is NOT gate.
2. (a) is NOT gate and (b) is OR gate.
3. (a) is AND gate and (b) is OR gate.
4. (a) is OR gate and (b) is AND gate.

A NAND gate connected as given in the figure,

The circuit operates like a:

1. NOT gate
2. OR gate
3. AND gate
4. None of these