An intrinsic semiconductor is converted into an \(\mathrm{n\text{-}}\)type extrinsic semiconductor by doping it with: 

1.	phosphorous	2.	aluminium
3.	silver	4.	germanium

To get output \(Y = 1\) in the given circuit which of the following input will be correct?

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

1. 5 mA
2. 10 mA
3. 15 mA
4. 20 mA

In the following figure, the diodes which are forward biased are:
 

(a)
(b)
(c)
(d)

1. (a), (b) and (d)
2. (c) only
3. (a) and (c)
4. (b) and (d)

Pure Si at \(500~\text{K}\) has an equal number of electron \((n_e)\) and hole\((n_h)\) concentrations of \(1.5\times10^{16}~\text{m}^{-3}\). Doping by indium increases \(n_h\) to \(4.5\times10^{22}~\text{m}^{-3}\).  The doped semiconductor is of:

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 gate

2. AND gate

3. NAND gate

4. NOR gate

Which of the following gate is called the universal gate? 
1. \(\mathrm{OR}\) gate 
2. \(\mathrm{AND}\) gate 
3. \(\mathrm{NAND}\) gate 
4. \(\mathrm{NOT}\) gate 

Out of the following which one is a forward-biased diode?

1.
2.
3.
4.

The following table is for which logic gate?

1. AND
2. OR
3. NAND
4. NOT

The following logic gate is: 

1. AND 

2. NAND 

3. EX-OR 

4. OR