Power Electronics Multiple Choice Questions on “The P-N Junction”.
1. The p-region has a greater concentration of __________ as compared to the n-region in a P-N junction.
A. holes
B. electrons
C. both holes & electrons
D. phonons
Answer: A
Clarification: Holes are the majority charge carriers in p-type material.
2. A p-type semiconductor material is doped with ____________ impurities whereas a n-type semiconductor material is doped with __________ impurities
A. acceptor, donor
B. acceptor, acceptor
C. donor, donor
D. donor, acceptor
Answer: A
Clarification: Donor impurities denote an electron to the n-type material making it a electron majority carrier & vice-versa.
3. In the p & n regions of the p-n junction the _________ & the ___________ are the majority charge carriers respectively.
A. holes, holes
B. electrons, electrons
C. holes, electrons
D. electrons, holes
Answer: C
Clarification: Holes are the majority charge carriers in p-type material & vice-versa.
4. The n-region has a greater concentration of _________ as compared to the p-region in a P-N junction diode.
A. holes
B. electrons
C. both holes & electrons
D. phonons
Answer: B
Clarification: Electrons are the majority charge carriers in n-type material.
5. Which of the below mentioned statements is false regarding a p-n junction diode?
A. Diode are uncontrolled devices
B. Diodes are rectifying devices
C. Diodes are unidirectional devices
D. Diodes have three terminals
Answer: D
Clarification: Diode is a two terminal device, anode & cathode are the two terminals.
6. In the p & n regions of the p-n junction the _________ & the ___________ are the minority charge carriers respectively.
A. holes, holes
B. electrons, electrons
C. holes, electrons
D. electrons, holes
Answer: D
Clarification: Holes are the minority charge carriers in n-type material & vice-versa.
7. Lets assume that the doping density in the p-region is 10-9 cm-3 & in the n-region is 10-17cm-3, as such the p-n junction so formed would be termed as a
A. p– n–
B. p+ n–
C. p– n+
D. p+ n+
Answer: B
Clarification: Doping density is greater in the p-region compared to the n-region.
8. When a physical contact between a p-region & n-region is established which of the following is most likely to take place?
A. Electrons from N-region diffuse to P-region
B. Holes from P-region diffuse to N-region
C. Both of the above mentioned statements are true
D. Nothing will happen
Answer: C
Clarification: When p & n region come together diffusion takes places & a depletion region is established with opposite charges on both the sides of the junction.
9. Which of the following is true in case of an unbiased p-n junction diode?
A. Diffusion does not take place
B. Diffusion of electrons & holes goes on infinitely
C. There is zero electrical potential across the junctions
D. Charges establish an electric field across the junctions
Answer: D
Clarification: A potential difference is established across the junctions due to recombination of holes & electrons. This growing filed (barrier potential) stops the further diffusion.
10. Which of the following is true in case of a forward biased p-n junction diode?
A. The positive terminal of the battery sucks electrons from the p-region
B. The positive terminal of the battery injects electrons into the p-region
C. The negative terminal of the battery sucks electrons from the p-region
D. None of the above mentioned statements are true