A \(\mathrm{p\text-n}\) photodiode is fabricated from a semiconductor with a band gap of \(2.5\) eV. It can detect a signal of wavelength:
1. \(6000~\mathring{A}\)
2. \(4000\) nm
3. \(6000\) nm
4. \(4000~\mathring{A}\)  

The symbolic representation of four logic gates is as shown:

(i)		(ii)
(ii)		(iv)

The logic symbols for OR, NOT, and NAND gates are respectively:
1. (iii), (iv), (ii)
2. (iv), (i), (iii)
3. (iv), (ii), (i)
4. (i), (iii), (iv)

The voltage gain of an amplifier with 9% negative feedback is 10. The voltage gain without feedback will be:

1. 90

2. 10

3. 1.25

4. 100

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

1. $10\times {10}^{14}$ $\mathrm{Hz}$

2. $5\times {10}^{14}$ $\mathrm{Hz}$

3. $1\times {10}^{14}$ $\mathrm{Hz}$

4. $20\times {10}^{14}$ $\mathrm{Hz}$

The circuit is equivalent to: 
     

1. AND gate
2. NAND gate
3. NOR gate
4. OR gate

In the following circuit, the output \(Y\) for all possible inputs \(A\) and \(B\) is expressed by the truth table: 
    

In the energy band diagram of a material shown below, the open circles and filled circles denote holes and electrons respectively. The material is a/an: 

1. p-type semiconductor

2. insulator

3. metal

4. n-type semiconductor

A transistor is operated in a common emitter configuration at constant collector voltage V_c = 1.5 V such that a change in the base current from 100 μA to 150 μA produces a change in the collector current from 5 mA to 10 mA. The current gain (β) is:

1. 67

2. 75

3. 100

4. 50

Which of the following is an example of forward biasing?
 

1.		2.
3.		4.

The following figure shows a logic gate circuit with two inputs A and B and the output C. The voltage waveforms of A, B, and C are as shown below:
   
The logic circuit gate is:

1. AND gate

2. NAND gate

3. NOR gate

4. OR gate