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. | \(\left(E_g\right)_C<\left(E_g\right)_{S i}\) |
In the given figure, the potential difference between A and B is:
1. | 0 | 2. | 5 volt |
3. | 10 volt | 4. | 15 volt |
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
When a p-n junction is forward biased, then:
1. | the depletion region becomes thick. |
2. | the p-side is at a higher potential than n side. |
3. | the current flowing is zero. |
4. | the effective resistance is of the order of \(10^6 ~\Omega\). |
If a small amount of aluminium is added to the silicon crystal:
1. | its resistance decreases. |
2. | it becomes a p-type semiconductor. |
3. | there will be fewer free electrons than holes in the semiconductor. |
4. | All of these are correct. |
If in a p-n junction, a square input signal of 10 V is applied as shown, then the output across RL will be:
1. | 2. | ||
3. | 4. |
The given graph represents the V-I characteristic for a semiconductor device. Which of the following statement is correct?
1. | It is a V-I characteristic for a solar cell where point A represents open-circuit voltage and point B represents short-circuit current. |
2. | It is for a solar cell and points A and B represent open-circuit voltage and current respectively. |
3. | It is for a photodiode and points A and B represent open-circuit voltage and current respectively. |
4. | It is for a LED and points A and B represent open-circuit voltage and short circuit current respectively. |
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
A Zener diode, having breakdown voltage equal to 15 V, is used in a voltage regulator circuit, as shown in the figure. The current through the diode is:
1. 10 mA
2. 15 mA
3. 20 mA
4. 5 mA
In a PN-junction diode:
1. | the current in the reverse biased condition is generally very small. |
2. | the current in the reverse biased condition is small but the forward-biased current is independent of the bias voltage. |
3. | the reverse-biased current is strongly dependent on the applied bias voltage. |
4. | the forward-biased current is very small in comparison to reverse-biased current. |