Practice Test: Semiconductor Electronics, Class 12, Physics JEE Notes | EduRev

 Page 1


 
 
Physics: Semiconductor Electronics Worksheet (XII) 
 
1. At absolute zero, Si acts as  
(A) non-metal      (B) metal 
(C) insulator      (D) none of these 
2. By increasing the temperature, the specific resistance of a conductor and a semiconductor  
(A) increases for both     (B) decreases for both  
(C) increases, decreases    (D) decreases, increases 
3. The energy band gap is maximum in  
(A) metals       (B) superconductors 
(C) insulators      (D) semiconductors  
4. The part of a transistor which is most heavily doped to produce large number of majority carries is  
(A) emitter      (B) base 
(C) collector      (D) can be any of the above three 
5. Formation of covalent bonds in compounds exhibits  
(A) wave nature of electron     (B) particle nature of electron  
(C) both wave and particle nature of electron  (D) none of these  
6. A strip of copper and another germanium are cooled from room temperature to 80 K. The resistance of  
(A) each of these decreases    
(B) copper strip increases and that of germanium  
(C) copper strip decreases and that of germanium increases  
(D) each of these increases  
7. The difference in the variation of resistance with temperature in a metal and a semiconductor arises 
essentially due to the difference in the  
(A) crystal structure  
(B) variation of the number of charge carries with temperature  
(C) type of bonding  
(D) variation of scattering mechanism with temperature  
8. In the middle of the depletion layer of a reversebiased p-n junction, the  
(A) electric field is zero     (B) potential is maximum  
(C) electric field is maximum    (D) potential is zero 
9. When npn transistor is used as an amplifier 
(A) electrons move from base to collector   (B) holes move form emitter to base 
(C) electrons move form collector to base  (D) holes move form base to emitter 
10. For a transistor amplifier in common emitter configuration for load impedance of 1 k ? (h
fe
 = 50 and h
ac
 = 
25) the current gain is  
(A) – 5.2       (B) – 15.7 
(C) – 24.8      (D) – 48.78  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 1 
 
Page 2


 
 
Physics: Semiconductor Electronics Worksheet (XII) 
 
1. At absolute zero, Si acts as  
(A) non-metal      (B) metal 
(C) insulator      (D) none of these 
2. By increasing the temperature, the specific resistance of a conductor and a semiconductor  
(A) increases for both     (B) decreases for both  
(C) increases, decreases    (D) decreases, increases 
3. The energy band gap is maximum in  
(A) metals       (B) superconductors 
(C) insulators      (D) semiconductors  
4. The part of a transistor which is most heavily doped to produce large number of majority carries is  
(A) emitter      (B) base 
(C) collector      (D) can be any of the above three 
5. Formation of covalent bonds in compounds exhibits  
(A) wave nature of electron     (B) particle nature of electron  
(C) both wave and particle nature of electron  (D) none of these  
6. A strip of copper and another germanium are cooled from room temperature to 80 K. The resistance of  
(A) each of these decreases    
(B) copper strip increases and that of germanium  
(C) copper strip decreases and that of germanium increases  
(D) each of these increases  
7. The difference in the variation of resistance with temperature in a metal and a semiconductor arises 
essentially due to the difference in the  
(A) crystal structure  
(B) variation of the number of charge carries with temperature  
(C) type of bonding  
(D) variation of scattering mechanism with temperature  
8. In the middle of the depletion layer of a reversebiased p-n junction, the  
(A) electric field is zero     (B) potential is maximum  
(C) electric field is maximum    (D) potential is zero 
9. When npn transistor is used as an amplifier 
(A) electrons move from base to collector   (B) holes move form emitter to base 
(C) electrons move form collector to base  (D) holes move form base to emitter 
10. For a transistor amplifier in common emitter configuration for load impedance of 1 k ? (h
fe
 = 50 and h
ac
 = 
25) the current gain is  
(A) – 5.2       (B) – 15.7 
(C) – 24.8      (D) – 48.78  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 1 
 
11. A piece of copper and another of germanium are cooled form room temperature to 77 K, the resistance of  
(A) each of them increases     (B) each of them decreases  
(C) copper decreases and germanium increase  (D) copper increases and germanium 
decrease  
12. The manifestation of band structure in solids is due to  
(A) Heisenberg’s uncertainty principle   (B) Pauli’s exclusion principle  
(C) Bohr’s correspondence principle   (D) Boltzmann’s law 
13. When p-n junction diode is forward biased, then  
(A) the depletion region is reduced and barrier height is increased 
(B) the depletion region is widened and barrier height is reduced  
(C) both the depletion region and barrier height are reduced  
(D) both the depletion region and barrier height are increased  
14. The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength 
shorter than 2480 nm is incident on it. The band gap in (eV) for the semiconductor is  
(A) 0.5 eV      (B) 0.7 eV 
(C) 1.1 eV      (D) 2.5 eV 
15. In a common base amplifier, the phase difference between the input signal voltage and output voltage is  
(A) 0       (B) p/2 
(C) p/4      (D) p 
16. In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple 
would be  
(A) 100 Hz       (B) 70.7 Hz 
(C) 50 Hz       (D) 25 Hz 
17. A solid which is transparent to visible light and whose conductivity increases with temperature is formed by  
(A) metallic binding      (B) ionic binding  
(C) covalent binding      (D) van der Waals binding  
18. In the ratio of the concentration of electrons that of holes in a semiconductor is 7/5 and the ratio of currents 
is 7/4 then what is the ratio of their drift velocities ?  
(A) 4/7      (B) 5/8 
(C) 4/5      (D) 5/4 
19. In common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. 
The value of the base current amplification factor ( ß) will be  
(A) 48      (B) 49 
(C) 50      (D) 51 
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 2 
 
Page 3


 
 
Physics: Semiconductor Electronics Worksheet (XII) 
 
1. At absolute zero, Si acts as  
(A) non-metal      (B) metal 
(C) insulator      (D) none of these 
2. By increasing the temperature, the specific resistance of a conductor and a semiconductor  
(A) increases for both     (B) decreases for both  
(C) increases, decreases    (D) decreases, increases 
3. The energy band gap is maximum in  
(A) metals       (B) superconductors 
(C) insulators      (D) semiconductors  
4. The part of a transistor which is most heavily doped to produce large number of majority carries is  
(A) emitter      (B) base 
(C) collector      (D) can be any of the above three 
5. Formation of covalent bonds in compounds exhibits  
(A) wave nature of electron     (B) particle nature of electron  
(C) both wave and particle nature of electron  (D) none of these  
6. A strip of copper and another germanium are cooled from room temperature to 80 K. The resistance of  
(A) each of these decreases    
(B) copper strip increases and that of germanium  
(C) copper strip decreases and that of germanium increases  
(D) each of these increases  
7. The difference in the variation of resistance with temperature in a metal and a semiconductor arises 
essentially due to the difference in the  
(A) crystal structure  
(B) variation of the number of charge carries with temperature  
(C) type of bonding  
(D) variation of scattering mechanism with temperature  
8. In the middle of the depletion layer of a reversebiased p-n junction, the  
(A) electric field is zero     (B) potential is maximum  
(C) electric field is maximum    (D) potential is zero 
9. When npn transistor is used as an amplifier 
(A) electrons move from base to collector   (B) holes move form emitter to base 
(C) electrons move form collector to base  (D) holes move form base to emitter 
10. For a transistor amplifier in common emitter configuration for load impedance of 1 k ? (h
fe
 = 50 and h
ac
 = 
25) the current gain is  
(A) – 5.2       (B) – 15.7 
(C) – 24.8      (D) – 48.78  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 1 
 
11. A piece of copper and another of germanium are cooled form room temperature to 77 K, the resistance of  
(A) each of them increases     (B) each of them decreases  
(C) copper decreases and germanium increase  (D) copper increases and germanium 
decrease  
12. The manifestation of band structure in solids is due to  
(A) Heisenberg’s uncertainty principle   (B) Pauli’s exclusion principle  
(C) Bohr’s correspondence principle   (D) Boltzmann’s law 
13. When p-n junction diode is forward biased, then  
(A) the depletion region is reduced and barrier height is increased 
(B) the depletion region is widened and barrier height is reduced  
(C) both the depletion region and barrier height are reduced  
(D) both the depletion region and barrier height are increased  
14. The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength 
shorter than 2480 nm is incident on it. The band gap in (eV) for the semiconductor is  
(A) 0.5 eV      (B) 0.7 eV 
(C) 1.1 eV      (D) 2.5 eV 
15. In a common base amplifier, the phase difference between the input signal voltage and output voltage is  
(A) 0       (B) p/2 
(C) p/4      (D) p 
16. In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple 
would be  
(A) 100 Hz       (B) 70.7 Hz 
(C) 50 Hz       (D) 25 Hz 
17. A solid which is transparent to visible light and whose conductivity increases with temperature is formed by  
(A) metallic binding      (B) ionic binding  
(C) covalent binding      (D) van der Waals binding  
18. In the ratio of the concentration of electrons that of holes in a semiconductor is 7/5 and the ratio of currents 
is 7/4 then what is the ratio of their drift velocities ?  
(A) 4/7      (B) 5/8 
(C) 4/5      (D) 5/4 
19. In common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. 
The value of the base current amplification factor ( ß) will be  
(A) 48      (B) 49 
(C) 50      (D) 51 
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 2 
 
20. If the lattice constant of this semiconductor is decreased, then which of the following is correct ?  
 
(A) all E
c
, E
g
, E
v
 decrease 
(B) all E
c
, E
g
, E
v
 increase     
(C) E
c
, and E
v
 increase, but E
g
 decreases  
(D) E
c
, and E
v
 decrease, but E
g
 increases.  
21. In the following, which one of the diodes is reverse biased ?  
(A) 
     
(B)  
(C)      (D)  
22. The circuit has two oppositely connect ideal diodes in parallel. What is the current following in circuit ?  
 
(A) 1.33 A       (B) 1.71 A 
(C) 2.00 A       (D) 2.31 A 
23. If in a p-n junction diode, a square input signal of 10 V is applied as shown  
 
Then the output signal across R
L
 will be  
(A)      (B)  
(C)      (D)  
24. Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the 
following statements is most appropriate ?  
(A) The number of free electrons for conduction is significant only in Si and Ge but small in C.  
(B) The number of free conduction electrons is significant in C but small in SI and Ge  
(C) The number of free conduction electrons is negligible small in all thee three 
(D) The number of free electrons for conduction is significant in all the three  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 3 
 
Page 4


 
 
Physics: Semiconductor Electronics Worksheet (XII) 
 
1. At absolute zero, Si acts as  
(A) non-metal      (B) metal 
(C) insulator      (D) none of these 
2. By increasing the temperature, the specific resistance of a conductor and a semiconductor  
(A) increases for both     (B) decreases for both  
(C) increases, decreases    (D) decreases, increases 
3. The energy band gap is maximum in  
(A) metals       (B) superconductors 
(C) insulators      (D) semiconductors  
4. The part of a transistor which is most heavily doped to produce large number of majority carries is  
(A) emitter      (B) base 
(C) collector      (D) can be any of the above three 
5. Formation of covalent bonds in compounds exhibits  
(A) wave nature of electron     (B) particle nature of electron  
(C) both wave and particle nature of electron  (D) none of these  
6. A strip of copper and another germanium are cooled from room temperature to 80 K. The resistance of  
(A) each of these decreases    
(B) copper strip increases and that of germanium  
(C) copper strip decreases and that of germanium increases  
(D) each of these increases  
7. The difference in the variation of resistance with temperature in a metal and a semiconductor arises 
essentially due to the difference in the  
(A) crystal structure  
(B) variation of the number of charge carries with temperature  
(C) type of bonding  
(D) variation of scattering mechanism with temperature  
8. In the middle of the depletion layer of a reversebiased p-n junction, the  
(A) electric field is zero     (B) potential is maximum  
(C) electric field is maximum    (D) potential is zero 
9. When npn transistor is used as an amplifier 
(A) electrons move from base to collector   (B) holes move form emitter to base 
(C) electrons move form collector to base  (D) holes move form base to emitter 
10. For a transistor amplifier in common emitter configuration for load impedance of 1 k ? (h
fe
 = 50 and h
ac
 = 
25) the current gain is  
(A) – 5.2       (B) – 15.7 
(C) – 24.8      (D) – 48.78  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 1 
 
11. A piece of copper and another of germanium are cooled form room temperature to 77 K, the resistance of  
(A) each of them increases     (B) each of them decreases  
(C) copper decreases and germanium increase  (D) copper increases and germanium 
decrease  
12. The manifestation of band structure in solids is due to  
(A) Heisenberg’s uncertainty principle   (B) Pauli’s exclusion principle  
(C) Bohr’s correspondence principle   (D) Boltzmann’s law 
13. When p-n junction diode is forward biased, then  
(A) the depletion region is reduced and barrier height is increased 
(B) the depletion region is widened and barrier height is reduced  
(C) both the depletion region and barrier height are reduced  
(D) both the depletion region and barrier height are increased  
14. The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength 
shorter than 2480 nm is incident on it. The band gap in (eV) for the semiconductor is  
(A) 0.5 eV      (B) 0.7 eV 
(C) 1.1 eV      (D) 2.5 eV 
15. In a common base amplifier, the phase difference between the input signal voltage and output voltage is  
(A) 0       (B) p/2 
(C) p/4      (D) p 
16. In a full wave rectifier circuit operating from 50 Hz mains frequency, the fundamental frequency in the ripple 
would be  
(A) 100 Hz       (B) 70.7 Hz 
(C) 50 Hz       (D) 25 Hz 
17. A solid which is transparent to visible light and whose conductivity increases with temperature is formed by  
(A) metallic binding      (B) ionic binding  
(C) covalent binding      (D) van der Waals binding  
18. In the ratio of the concentration of electrons that of holes in a semiconductor is 7/5 and the ratio of currents 
is 7/4 then what is the ratio of their drift velocities ?  
(A) 4/7      (B) 5/8 
(C) 4/5      (D) 5/4 
19. In common base mode of a transistor, the collector current is 5.488 mA for an emitter current of 5.60 mA. 
The value of the base current amplification factor ( ß) will be  
(A) 48      (B) 49 
(C) 50      (D) 51 
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 2 
 
20. If the lattice constant of this semiconductor is decreased, then which of the following is correct ?  
 
(A) all E
c
, E
g
, E
v
 decrease 
(B) all E
c
, E
g
, E
v
 increase     
(C) E
c
, and E
v
 increase, but E
g
 decreases  
(D) E
c
, and E
v
 decrease, but E
g
 increases.  
21. In the following, which one of the diodes is reverse biased ?  
(A) 
     
(B)  
(C)      (D)  
22. The circuit has two oppositely connect ideal diodes in parallel. What is the current following in circuit ?  
 
(A) 1.33 A       (B) 1.71 A 
(C) 2.00 A       (D) 2.31 A 
23. If in a p-n junction diode, a square input signal of 10 V is applied as shown  
 
Then the output signal across R
L
 will be  
(A)      (B)  
(C)      (D)  
24. Carbon, silicon and germanium have four valence electrons each. At room temperature which one of the 
following statements is most appropriate ?  
(A) The number of free electrons for conduction is significant only in Si and Ge but small in C.  
(B) The number of free conduction electrons is significant in C but small in SI and Ge  
(C) The number of free conduction electrons is negligible small in all thee three 
(D) The number of free electrons for conduction is significant in all the three  
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 3 
 
25. A working transistor with its three legs marked P, Q and R is tested using a multimeter. No conduction is 
found between P and Q. By connecting the common (negative) terminal of the multimeter to R and the 
other (positive) terminal to P or Q, some resistance is seen on the mulitmeter. Which of the following is true 
for the transistor ?  
(A) It is an npn transistor with R as collector   
(B) It is an npn transistor with R as base  
(C) It is a pnp transistor with R as collector  
(D) It is a pnp transistor with R as emitter  
26. In the circuit below, A and B represent two inputs and C represents the output. The circuit represents  
 
(A) OR gate      (B) NOR gate 
(C) AND gate      (D) NAND gate 
 
 
 
 
 
ANSWERS 
1. (C) 
2. (C) 
3. (C) 
4. (A) 
5. (A) 
6. (C) 
7. (B) 
8. (A) 
9. (A) 
10. (D) 
11. (C) 
12. (B) 
13. (C) 
14. (A) 
15. (A) 
16. (A) 
17. (C) 
18. (D) 
19. (B) 
20. (D) 
21. (A) 
22. (C) 
23. (A) 
24. (A) 
25. (A) 
26. (A) 
 
GIITJEE (Chandigarh Limited) SCO 382, Sector 37 – D, Chandigarh Phone No. 0172 – 2628810, 2628811, 4652111   P – 4