31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - NEET MCQ

# 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - NEET MCQ

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## 25 Questions MCQ Test Physics Class 12 - 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 for NEET 2024 is part of Physics Class 12 preparation. The 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 questions and answers have been prepared according to the NEET exam syllabus.The 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 MCQs are made for NEET 2024 Exam. Find important definitions, questions, notes, meanings, examples, exercises, MCQs and online tests for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 below.
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31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 1

### Sodium has body-centered packing. The distance between the two nearest atoms is 3.7 Å. The lattice parameter is: [2009]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 1

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 2

### Which one of the following statements is false?    [2010]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 2

The majority carriers in an n-type semiconductor are electrons.

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31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 3

### Which one of the following bonds produces a solid that reflects light in the visible region and whose electrical conductivity decreases with temperature and has a high melting point?    [2010]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 3

Metals (metallic bonds) have these physical properties:

• Metals reflect the photons of the visible spectrum (light) falling on their surface, thus metals are often silver-white or greyish with the characteristic specular reflection of metallic lustre.
• The electrical conductivity of metals decreases with a rise in temperature.
• Metals have a high melting point.
31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 4

The device that can act as a complete electronic circuit is:
[2010]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 4

Integrated circuit can act as a complete
electronic circuit.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 5

A common emitter amplifier has a voltage gain of 50, an input impedance of 100 Ω and an output impedance of 200 Ω. The power gain of the amplifier is:
[2010]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 5

Power gain = Voltage gain * Current gain

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 6

To get an output Y = 1 from the circuit shown below, the input must be:
[2010]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 6

For (a) & (c) we get output 1.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 7

For transistor action:
(1) Base, emitter and collector regions should have similar size and doping concentrations.
(2) The base region must be very thin and lightly doped.
(3) The emitter-base junction is forward biased and the base-collector junction is reverse biased.
(4) Both the emitter-base junction as well as the base-collector junction are forward biased.

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 7
• For transistor action, the base region must be very thin and lightly doped.
• Also, the emitter-base junction is forward biased and the base-collector junction is reverse biased.
31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 8

The following Figure shows a logic gate circuit with two inputs A and B and the output Y. The voltage waveforms of A, B and Y are given:

The logic gate is:

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 8

From the given waveforms, the truth table
is as follows:

The above truth table is for the NAND gate.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 9

A transistor is operated in common emitter configuration at VC = 2V such that a change in the base current from 100 μA to 300 μA produces a change in the collector current from 10 mA to 20 mA. The current gain is:
[2011]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 9

The current gain:

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 10

In forward biasing of the p–n junction:
[2011]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 10

In forward biasing of the p-n junction, the positive terminal of the battery is connected to the p-side and the negative terminal of the battery is connected to the n-side. The depletion region becomes thin.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 11

Symbolic representation of four logic gate are shown as:   [2011]
(i)

(ii)

(iii)

(iv)
Pick out which ones are for AND, NAND and NOT gates, respectively.

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 11

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 12

If a small amount of antimony is added to germanium crystal then:
[2011]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 12
• When a small amount of antimony (pentavalent) is added to the germanium crystal then the crystal becomes an n-type semiconductor.
• Therefore, there will be more free electrons than holes in the semiconductor.
31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 13

In the following figure, the diodes which are forward biased are:
[2011M]

(i)

(ii)

(iii)

(iv)

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 13

Only in (A) and (C) diodes are forward biased as p-type should be at higher potential and n-type at lower potential.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 14

Pure Si at 500K has an equal number of electrons (ne) and hole (nh) concentrations of 1.5 × 1016 m–3. Doping by indium increases nto 4.5 × 1022 m–3. The doped semiconductor is of:
[2011M]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 14

ne = 5 × 10& nh = 4.5 × 1022
⇒ nh >> ne
∴ Semiconductor is p-type and ne = 5 * 109 m–3.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 15

A Zener diode, having a breakdown voltage equal to 15V, is used in a voltage regulator circuit shown in the figure. The current through the diode is:
[2011M]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 15

The voltage across the Zener diode is constant.

Current in 1kΩ resistor = I1kΩ = 15 Volt / 1 kΩ = 15 mA
Current in 250Ω resistor = I250Ω = (20 - 15) / 250 = 5V/250 = 20 mA
Izener diode = (20 - 15) = 5 mA

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 16

Two ideal diodes are connected to a battery as shown in the circuit. The current supplied by the battery is:

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 16

Here D1 is in forward bias and D2 is in
reverse bias. So, D1 will conduct and D2 will not conduct. Thus, no current will flow through DC.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 17

In a CE transistor amplifier, the audio signal voltage across the collector resistance of 2kΩ is 2V. If the base resistance is 1kΩ and the current amplification of the transistor is 100, the input signal voltage is:
[2012]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 17

The output voltage, across the load RC
V0 = IC RC = 2
Collector current (IC):

Current gain (β):

Input voltage (Vi):

Vi = IBRB = 10–5 * 103 = 10–2 Volt
Vi = 10 mV

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 18

C and Si both have the same lattice structure, having 4 bonding electrons in each. However, C is an insulator whereas Si is an intrinsic semiconductor. This is because:
[2012]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 18

The four bonding electrons in the case of C lie in the second orbit, whereas in the case of Si they lie in the third orbit so loosely bounded valence electrons in Si as compared to C.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 19

Transfer characteristics [output voltage (V0) vs input voltage (V1)] for a base biased transistor in CE configuration is as shown in the figure. For using a transistor as a switch, it is used:
[2012]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 19

In the given graph:

• Region (I) Cut-off region
• Region (II) Active region
• Region (III) Saturation region

Transistor as a switch is used in the cut-off or saturation region. So the correct option is B.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 20

The figure shows a logic circuit with two inputs A and B and the output C. The voltage waveforms across A, B and C are given. The logic circuit gate is:
[2012]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 20

According to the truth table, we can clearly see that it is an OR Gate

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 21

The input resistance of a silicon transistor is100 Ω. Base current is changed by 40 μA which results in a change in collector current by 2 mA. This transistor is used as a common emitter amplifier with a load resistance of 4 KΩ. The voltage gain of the amplifier is:
[2012M]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 21

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 22

To get an output Y = 1 in the given circuit which of the following input will be correct:
[2012M]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 22
• C should be always 1 and at least one of A & B should be 1 (as they are connected to OR Gate) to get Y = 1
• Option (b) is the only option where C = 1 and at least one of A & B is 1 (A = 1 & B = 0)
31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 23

In an n-type semiconductor, which of the following statement is true?
[2013]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 23

In an n-type semiconductor, holes are minority carriers and pentavalent atoms are dopants.

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 24

In a common emitter (CE) amplifier having a voltage gain G, the transistor used has transconductance 0.03 mho and a current gain of 25. If the above transistor is replaced with another one with transconductance 0.02 mho and a current gain of 20, the voltage gain will be:
[2013]

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 24

Putting this value of Rin in equation (i):

From eqs. (ii) and (iii) we get:
Voltage gain of new transistor,

31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 25

The output (X) of the logic circuit shown in figure will be:

Detailed Solution for 31 Year NEET Previous Year Questions: Semiconductor Electronics - 1 - Question 25

Output X = A.B

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