Semiconductor Physics - NEET Physics Questions

Question 21: easy

A p–n photodiode is made of a material with a band gap of 2.0 eV. The minimum frequency of the radiation that can be absorbed by the material is nearly :

1. \[1\times 10_{14} Hz\]

2. \[20\times 10_{14} Hz\]

3. \[10\times 10_{14} Hz\]

4. \[5\times 10_{14} Hz\]

View Answer

Energy of EM wave E = hυ

⇒ 2 eV = 6.626 × 10^-34×υ

⇒ \[v= 5\times 10_{14} Hz\]

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Question 22: moderate

The logic circuit shown below has the input waveforms ‘A’ and ‘B’ as shown. Pick out the correct output waveform.

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Question 23: moderate

To get an output 1 from the circuit shown in the figure, the input may be :

1. A = 0, B = 1, C = 0

2. A = 1, B = 0, C = 0

3. A = 1, B = 0, C = 1

4. A = 1, B = 1, C = 0

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Question 24: moderate

The combination of ‘NAND’ gates shown here under (figure) are equivalent to

1. An OR gate and an AND gate respectively

2. An AND gate and a NOT gate respectively

3. An AND gate and an OR gate respectively

4. An OR gate and a NOT gate respectively

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Question 25: moderate

In the following circuit the equivalent resistance between A and B is

1. 20/3 Ω

2. 10 Ω

3. 16 Ω

4. 20 Ω

View Answer

Both the diodes are reversed biased so can be replaced by open circuit.

Req= 8+2+6= 16 ohm

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Question 26: moderate

GaAs (with a band gap = 1.5 eV) as an LED can emit :

1. Blue light

2. Green light

3. Infrared rays

4. Ultraviolet rays

View Answer

GaAs (Gallium Arsenide) with a band gap of 1.5 eV can emit light in the infrared region of the electromagnetic spectrum.

The energy of a photon emitted by an LED is related to its wavelength by the equation:

$E = \frac{hc}{\lambda}$

Solving we get

$λ= 826 nm which lies in infrared region.💬 Discuss this QuestionQuestion 27: moderate If break down voltage of zener diode is 6 V then value of I2 will be : 1. 18 mA 2. 24 mA 3. 6 mA 4. Zero View Answer Voltage across 500 ohm resistor = 12 Volt I = 12/500 = 24 mA I 1 = 6/1000= 6mA I2= I - I1= (24-6 )mA= 18 mA 💬 Discuss this QuestionQuestion 28: moderate The following configuration of gate is equivalent to 1. NAND 2. XOR 3. OR 4. None of these View Answer 💬 Discuss this QuestionQuestion 29: moderate Determine V0 for the network 1. 6.6 V 2. 9 V 3. -9 V 4. -6.6 V View Answer Both the diodes are forward biased so current will flow through the circuit i= 10/4.5= 20/9 mA V0= i R= (20/9)×3.3 Volt= 6.6 volt 💬 Discuss this QuestionQuestion 30: moderate 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 as given: The logic gate is : 1. OR 2. AND 3. NAND 4. NOR View Answer 💬 Discuss this Question« Previous 12345 Next »document.addEventListener('DOMContentLoaded', function () {
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