Semiconductor Physics - NEET Physics Questions
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Semiconductor Physics

Question 11: 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 12: 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 13: 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
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Both the diodes are reversed biased so can be replaced by open circuit.

Req= 8+2+6= 16 ohm

Question 14: 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
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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=hcλE = \frac{hc}{\lambda}

Solving we get

λ= 826 nm which lies in infrared region. 

 

Question 15: 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

Question 16: moderate

The following configuration of gate is equivalent to

1. NAND
2. XOR
3. OR
4. None of these
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Question 17: 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

Question 18: 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
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Question 19: moderate

Figure gives a system of logic gates. From the study of truth table it can be found that to produce a high output (1) at R, we must have :

1. X = 0, Y = 1
2. X = 1, Y = 1
3. X = 1, Y = 0
4. X = 0, Y = 0
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Question 20: moderate

In a given circuit as shown the two input wave form A and B are applied simultaneously. The
resultant waveform Y is :

1.
2.
3.
4.
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