C, Si, and Ge have the same lattice structure. Why is the C insulator?
1. | because ionization energy for C is the least in comparison to Si and Ge. |
2. | because ionization energy for C is highest in comparison to Si and Ge. |
3. | the number of free electrons for conduction in Ge and Si is significant but negligibly small for C. |
4. | both (2) and (3). |
1. | 5×1022 m−3,4.5×109 m−3 |
2. | 4.5×109 m−3,5×1022 m−3 |
3. | 5×1022 m−3,5×1022 m−3 |
4. | 4.5×109 m−3,4.5×109 m−3 |
Why can't we take one slab of p-type semiconductor and physically join it to another slab of n-type semiconductor to get a p-n junction?
1. | the diffusion of majority charge carriers will not occur. |
2. | the junction will behave as a discontinuity for the flowing charge carriers. |
3. | the junction will behave as a continuity for the flowing charge carriers. |
4. | both (1) and (2). |
The V-I characteristic of a silicon diode is shown in the figure. The resistance of the diode at ID=15 mA is:
1. 20 Ω
2. 30 Ω
3. 15 Ω
4. 10 Ω
The (V-I) characteristic of a silicon diode is shown in the figure. The resistance of the diode at VD=−10 V is:
1. 1×107 Ω
2. 2×107 Ω
3. 3×107 Ω
4. 4×107 Ω
Which one of the following is not true for the photodiodes?
1. | The current in the forward bias is more than the current in the reverse bias. |
2. | Photodiodes are preferably used in the reverse bias condition for measuring light intensity. |
3. | Photodiodes are preferably used in the forward bias condition for measuring light intensity |
4. | In photodiodes, only a small portion of the incident photons gets converted to electric current. |
Which material is preferred for solar cells?
1. Si
2. GaAs
3. CdS
4. both Si and GaAs
The output waveform (Y) of the AND gate for the following inputs A and B given in the figure is:
1. | |
2. | |
3. | |
4. | None of these |
The output waveform (Y) of the OR gate for the following inputs A and B given in the figure is:
1. | ![]() |
2. | ![]() |
3. | ![]() |
4. | none of these |