The Correct Answer is (A)
The width of depletion layer will increase with reverse bias.
Topic 2 : PN Junction Diode
1. The increase in the width of the depletion region in a p-n junction diode is due to :⇒ ( NEET 2020 Phase 1)
A. reverse bias only
B. both forward bias and reverse bias
C. increase in forward current
D. forward bias only
2. In a p-n junction diode, change in temperature due to heating ⇒ ( NEET 2018)
A. affects only reverse resistance
B. affects only forward resistance
C. does not affect resistance of p-n junction
D. affects the overall V - I characteristics of p-n junction
The Correct Answer is (D)
As a result of heating, temperature increases
which generates large number of electron-hole
pairs which lead to increase in conductivity. As
current increases I = I0(), overall resistance of
diode changes which affects forward and reversed
biasing.
3.
The barrier potential of a p-n junction depends on
(1) type of semiconductor material
(2) amount of doping
(3) temperature
Which one of the following is correct ? ⇒ (AIPMT 2014)
A. (1) and (2) only
B. (2) only
C. (2) and (3) only
D. (1), (2) and (3)
The Correct Answer is (D)
The barrier potential depends on type of semiconductor (For Si, Vb = 0.7 V and for Ge, Vb = 0.3 V), amount of doping and also on the temperature.
4. In an unbiased p-n junction, holes diffuse from the p-region to n-region because of ⇒ (NEET 2013 (Karnataka))
A. The attraction of free electrons of n-region.
B. The higher hole concentration in p-region than that in n-region.
C. The higher concentration of electrons in the n-region than that in the p-region.
D. The potential difference across the p-n junction.
The Correct Answer is (B)
The higher hole concentration is in p-region than that in n-region.
5. In forward biasing of the p-n junction ⇒ (AIPMT 2011 Prelims)
A. the positive terminal of the battery is connected to p-side and the depletion region becomes thick.
B. the positive terminal of the battery is connected to n-side and the depletion region becomes thin.
C. the positive terminal of the battery is connected to n-side and the depletion region becomes thick.
D. the positive terminal of the battery is connected to p-side and the depletion region becomes thin.
The Correct Answer is (D)
In forward biasing, the positive terminal of the battery is connected to p-side and the negative terminal to n-side of p-n junction. The forward bias voltage opposes the potential barrier. Due to it, the depletion region becomes thin.
6. Application of a forward bias to a p-n junction ⇒ (AIPMT 2005)
A. widens the depletion zone
B. increases the potential difference across the depletion zone
C. increases the number of donors on the n side
D. decreases the electric field in the depletion zone.
The Correct Answer is Option (D)
Number of donors is more because electrons from –ve terminal of the cell pushes (enters) the n side and decreases the number of uncompensated pentavalent ion due to which potential barrier is reduced. The neutralised pentavalent atom are again in position to donate electrons.
7. Reverse bias applied to a junction diode ⇒ (AIPMT 2003)
A. lowers the potential barrier
B. raises the potential barrier
C. increases the majority carrier current
D. increases the minority carrier current
The Correct Answer is Option (B)
In reverse bias, the size of the depletion region increases thereby increasing the potential barrier
8. Barrier potential of a p-n junction diode does not depened on ⇒ ( AIPMT 2003)
A. diode design
B. temperature
C. forward bias
D. doping density
The Correct Answer is Option (A)
Barrier potential does not depend in diode design while barrier potential depends upon temperature, doping density and forward biasing.