The energy band diagrams for semiconductor samples of silicon are as shown. We can assert that:
1. | Sample \(X\) is undoped while samples \(Y\) and \(Z\) have been doped with a third group and a fifth group impurity respectively. |
2. | Sample \(X\) is undoped while both samples \(Y\) and \(Z\) have been doped with a fifth group impurity. |
3. | Sample \(X\) has been doped with equal amounts of third and fifth group impurities while samples \(Y\) and \(Z\) are undoped. |
4. | Sample \(X\) is undoped while samples \(Y\) and \(Z\) have been doped with a fifth group and a third group impurity respectively. |
An LED is constructed from a \(\mathrm{p\text{-}n}\) junction diode using \(\mathrm{GaAsP}\). The energy gap is \(1.9~\text{eV}\). The wavelength of the light emitted will be equal to:
1. \(10.4 \times 10^{-26} \text{m}\)
2. \(654~ \text{nm}\)
3. \(654~ \text{m}\)
4. \(654\times 10^{-11}~\text{m}\)
1. | \(1.0 \times 10^6 ~\text{V/m}\) | 2. | \(1.0 \times 10^5 ~\text{V/m}\) |
3. | \(2.0 \times 10^5 ~\text{V/m}\) | 4. | \(2.0 \times 10^6 ~\text{V/m}\) |
In an NPN transistor amplifier, if 98% of electrons emitted from the emitter reach the collector, then the value of collector current for the base current of 40 A will be:
1. 1.96 mA
2. 1.92 mA
3. 1.96 A
4. 1.92 A
In a common emitter amplifier, the phase difference between input signal and output signal is:
1. zero
2.
3.
4.
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. \(10^{6}\)
In a common emitter circuit, if VCC is changed by 0.2 V, collector current changes by 4 x 10–3 mA. The output resistance will be:
1. 10 k
2. 30 k
3. 50 k
4. 70 k
When a transistor is used as a switch, it is in:
1. active state.
2. cut-off state.
3. saturation state.
4. both cut-off and saturation states are possible.
Use of transistor as an amplifier works in the:
1. Cut off region
2. Saturation region
3. Passive region
4. Active region
1. | \(5\) A | 2. | \(0.2\) A |
3. | \(0.6\) A | 4. | zero |