1. In p-n-p transistor the current IE has two components viz. IEP due to injection of holes from p-region to n-region and IE due to injection of electrons from n-region to p-region. Then
2. In an n channel JFET, the gate is
3. The amount of photoelectric emission current depends on
4. Assertion (A): A p-n junction has high resistance in reverse direction. Reason (R): When a reverse bias is applied to p-n junction, the width of depletion layer increases.
5. In the circuit of figure the function of resistor R and diode D are
6. At very high temperatures the extrinsic semi conductors become intrinsic because
7. When a voltage is applied to a semiconductor crystal then the free electrons will flow.
8. Ferrite have
9. In a p type material the Fermi level is 0.3 eV above valence band. The concentration of acceptor atoms is increased. The new position of Fermi level is likely to be
10. In an n-p-n transistor, the majority carriers in the base are
11. An LED has a rating of 2 V and 10 mA. It is used along with 6V battery. The range of series resistance is
12. The number of doped regions in PIN diode is
13. A silicon (PN) junction at a temperature of 20°C has a reverse saturation current of 10 pico Ampere. The reverse saturation current at 40°C for the same bias is approximately.
14. In a bipolar transistor the barrier potential
15. Recombination produces new electron-hole pairs
16. An amplifier without feedback has a voltage gain of 50, input resistance of 1 kΩ and output resistance of 2.5 kΩ. The input resistance of the current shunt -ve feedback amplifier using the above amplifier with a feedback factor of 0.2 is
17. As compared to an ordinary semiconductor diode, a Schottky diode
18. Assertion (A): When a high reverse voltage is applied to a p-n junction the diode breaks down. Reason (R): High reverse voltage causes Avalanche effect.
19. Crossover distortion behaviour is characteristic of
20. If a ac for transistor is 0.98 then βac is equal to
21. Assertion (A): The conductivity of p type semiconductor is higher than that of intrinsic semiconductor. Reason (R): The addition of donor impurity creates additional energy levels below conduction band.
22. In an n-p-n transistor biased for operation in forward active region
23. An increase in temperature increases the width of depletion layer.
24. A zener diode is used in
25. A particular green LED emits light of wavelength 5490, Å, the energy bandgap of the semiconductor material used there is .. h = 6.6 x 10-34 J sec.