# Physics class12th Chapter14 ELECTRONIC DEVICES VVI Objective Question

Q.1. Main Gate (Baisc Gate) is

(A) AND, OR

(B) NAND, NOR

(C) OR, NOT

(D) AND, OR, NOT

Ans :- (D)

Q.2. Write the decimal number 25 in binary

(A) (1100)₂

(B) (1001)₂

(C) (11001)₂

(D) (11101)₂

Ans :- (C)

Q.3. How many transistor are used for NOT – gate ?

(A) 1

(B) 3

(C) 2

(D) None of these

Ans :- (A)

Q.4. Write the crease of temperature, the resistance of a semiconductor

(A) increases

(B) decreases

(C) sometime increases and sometime decreases

(D) remains unchanged

Ans :- (B)

Q.5. How many semiconductor diodes are used for OR-gate ?

(A) 2

(B) 3

(C) 1

(D) None of these

Ans :- (A)

Q.6. Which of the following are the universal gate

(A) NOR- gate

(B) NAND- gate

(C) AND- gate

(D) Both ‘A’ and ‘B’

Ans :- (D)

Q.7. If the current constant for a transistor are α and β then

(A) αβ = 1

(B) β>1 , α<1

(C) α=β

(D) β<1 ,α>1

Ans :- (B)

Q.8. Which of the following logic gate is a universal gates ?

(A) OR- gate

(B) NOR- gate

(C) AND- gate

(D) NOT- gate

Ans :- (B)

Q.9. A semiconductor is cooled from T₁K to T₂K then its resistance will

(A) increase

(B) decrease

(C) remain constant

(D) first decrease then increase

Ans :- (B)

Q.10. Which of the following gate not contains transistor

(A) NOR- gate

(B) AND- gate

(C) NOT- gate

(D) None of these

Ans :- (B)

Q.11. How many semiconductor diodes are used for AND- gate ?

(A) 1

(B) 3

(C) 2

(D) 4

Ans :- (C)

Q.12. For a transistor β is 24, the value of α is

(A) 1

(B) 0.96

(C) 0.50

(D) 0.25

Ans :- (B)

Q.13. In n-p-n transistor the relation between emitter current i, base current i, and collector current i, is

(A) Ic = Ie – Ib

(B) Ib = Ie + Ic

(C) Ie = Ic + Ib

(D) None of these

Ans :- (C)

Q.14. At absolute zero, Si acts as

(A) Non- metal

(B) Metal

(C) Insulator

(D) None of these

Ans :- (C)

Q.15. Transistor is a/an

(A) Chip

(B) insulator

(C) Semiconductor

(D) metal

Ans :- (C)

(A) Copper

(B) Sillicon

(C) aluminium

(D) Constantan

Ans :- (B)

Q.17. Drift current in a p-n junction is due to

(A) electric field

(B) Charge carriers density

(C) Collision of electrons

(D) None of the above

Ans :- (B)

Q.18. The ratio of power gain and resistance in case of common base amplifier is

(A) α

(B) α²

(C) α³

(D) α⁴

Ans :-(B)

Q.19. In boolean algebra if A=B=1 then the value of (A·B+A) is

(A) A

(B) B

(C) A+B

(D) all of above

Ans :- (D)