In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an:
1. | p-type semiconductor |
2. | insulator |
3. | metal |
4. | n-type semiconductor |
Identify the incorrect statement from the following:
1. | The resistivity of a semiconductor increases with an increase in temperature. |
2. | Substances with an energy gap of the order of 10 eV are insulators. |
3. | In conductors, the valence and conduction bands may overlap. |
4. | The conductivity of a semiconductor increases with an increase in temperature. |
Carbon, Silicon, and Germanium atoms have four valence electrons each. Their valence and conduction bands are separated by energy gaps represented by \(\left(E_g\right)_C,(E_g)_{Si}~\text{and}~(E_g)_{Ge}\) respectively. Which one of the following relationships is true in their case?
1. | \(\left(E_g\right)_C<\left(E_g\right)_{G e} \) | 2. | \(\left(E_g\right)_C>\left(E_g\right)_{S i} \) |
3. | \(\left(E_g\right)_C=\left(E_g\right)_{S i} \) | 4. | \(\left(E_g\right)_C<\left(E_g\right)_{S i}\) |
A semiconductor is known to have an electron concentration of cm-3 and a hole concentration of cm-3. The semiconductor is:
1. n-type
2. p-type
3. intrinsic
4. insulator
C and Si both have the same lattice structure, having 4 bonding electrons in each. However, C is an insulator whereas Si is an intrinsic semiconductor. This is because:
1. | in the case of C, the valence band is not completely filled at absolute zero temperature. |
2. | in the case of C, the conduction band is partly filled even at absolute zero temperature. |
3. | the four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si, they lie in the third. |
4. | the four bonding electrons in the case of C lie in the third orbit, whereas for Si, they lie in the fourth orbit. |
Pure Si at 500 K has equal number of electron and hole concentration of Doping by indium increases to The doped semiconductor is of:
1. | n-type with electron concentration \(n_{e}=5\times10^{22}~m^{-3}\) |
2. | \(n_{e}=2.5\times10^{23}~m^{-3}\) | p-type with electron concentration
3. | \(n_{e}=2.5\times10^{10}~m^{-3}\) | n-type with electron concentration
4. | \(n_{e}=5\times10^{9}~m^{-3}\) | p-type with electron concentration
If the reverse bias in a junction diode is changed from \(5\) V to \(15\) V then the value of current changes from \(38\) \(\mu \text{A}\) to \(88\) \(\mu \text{A}.\) The resistance of junction diode will be:
1. \(4\times10^{5}\)
2. \(3\times10^{5}\)
3. \(2\times10^{5}\)
4. \(10^{6}\)
The given circuit has two ideal diodes connected as shown in the figure below. The current flowing through the resistance R1 will be:
1. | 2.5 A | 2. | 10.0 A |
3. | 1.43 A | 4. | 3.13 A |
What is the reading of the ideal ammeters A1 and A2 connected in the given circuit diagram, if junction diodes are ideal?
1. 2 A and zero
2. 3 A and 2 A
3. 2 A and 3 A
4. Zero and 2 A