Page 104 - Physics - XII

Q2. The dominant mechanism for motion of charge carriers in forward and reverse biased silicon
p-n junction are

(a) drift in forward bias, diff usion in reverse bias.
(b) diff usion in forward bias, drift in reverse bias.
(c) diff usion in both forward and reverse bias.
(d) drift in both forward and reverse bias.

Q3. A forward biased diode is

(a) 0 V –2 V (b) –4 V –3 V

(c) 3 V 5 V (d) –2 V +2 V

Q4. Which of the junction diodes shown below are forward biased?
(a) –10 V (b) +10 V

R R
–5 V +5 V

(c) R (d) R

–10 V –5 V

Q5. Potential barrier developed in a junction diode opposes the fl ow of
(a) minority carrier in both regions only (b) majority carriers only
(c) electrons in p-region (d) holes in p-region

Q6. Current through the ideal diode as shown in fi gure is 100 Ω
(a) zero (b) 20 A
2 V 5 V
(c) 1 A (d) 1 A
20 50
Q7. Which of the following statements is correct?
(a) Hole is an antiparticle of electron.

(b) Hole is a vacancy created when an electron leaves a covalent bond.
(c) Hole is the absence of free electrons.
(d) Hole is an artifi cially created particle.

Q8. In a n-type semiconductor, which of the following statements is true?

(a) Electrons are majority carriers and trivalent atoms are the dopants.
(b) Electrons are minority carriers and pentavalent atoms are dopants.
(c) Holes are minority carriers and pentavalent atoms are dopants.

(d) Holes are majority carriers and trivalent atoms are dopants.

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