CBSE Class 12 Physics Chapter-14 Important Questions – Free PDF Download
Free PDF download of Important Questions with Answers for CBSE Class 12 Physics Chapter 14 – Semiconductor Electronic: Material, Devices And Simple Circuits 1 Mark Questions prepared by expert Physics teachers from latest edition of CBSE(NCERT) books only by CoolGyan to score more marks in CBSE board examination.
CBSE Class 12 Physics Chapter 14 – Semiconductor Electronic: Material, Devices And Simple Circuits
CBSE Class 12 Physics Important Questions Chapter 14 – Semiconductor Electronic: Material, Devices And Simple Circuits
1 Mark Questions
1.Give the ratio of number of holes and the no. of conduction electrons in an intrinsic semiconductor.
Ans.
(As in intrinsic semiconductor ne = nh)
2.What type of impurity is added to obtain n-type semiconductor?
Ans. Pentavalent atoms like Arsenic (As)
3.Doping of silicon with indium leads to which type of semiconductor?
Ans.Indium is a trivalent impurity, thus doping of silicon with indium leads to p-type semiconductor.
4.Draw an energy level diagram for an intrinsic semiconductor?
Ans.In intrinsic semiconductor (ne = nh)
5. A semiconductor has equal electron and hole concentration of
. On doping
with a certain impurity electron concentration increases to
. Identify the type of semiconductor after doping?
Ans.As ne > nh, thus resulting semiconductor is of n-type.
6.How does the energy gap of an intrinsic semiconductor vary, when doped with a trivalent impurity?
Ans. When a trivalent impurity is added to an intrinsic semiconductor, an acceptor energy level is created in the forbidden energy gap which lies above the valence band. Due to this electrons easily transformed to the acceptor energy level.
7. How does width of depletion layer of p.n junction diode change with decrease in reverse bias?
Ans.Decrease in reverse bias will decrease in width of the depletion layer.
8. Under what condition does a junction diode work as open switch?
Ans. A junction diode works an open switch when it is reverse biased.
9. Which type of biasing gives a semiconductor diode very high resistance?
Ans.Reverse biasing
10. If The output of a 2-input NAND gate is fed as the input to a NOT gate
(i) name the new logic gate obtained and
(ii) write down its truth table?
Ans. Logic gate obtained is AND gate.
| A | B | Y |
| 0 1 1 | 0 1 1 | 0 1 |
11.Define current amplification factor in a common – emitter mode of transistor?
Ans. Ratio of small change in collection current to the small change in base current at constant collector emitter junction voltage is called current amplification factor.
12.Why is a semiconductor damaged by a strong current?
Ans.When a strong current passes through a semiconductor large amount of heat is produced which breaks the covalent bonds in the semiconductor due to which it gets damaged.
