In a semiconductor, 2/3rd of the total current is carried by electrons and remaining 1/3rd by the holes. If at this temperature, the drift velocity of electrons is 3 times that of holes, the ratio of number density of electrons to that of holes is

• $\frac{3}{2}$

• $\frac{2}{3}$

• $\frac{5}{3}$

• $\frac{3}{3}$

In an p-n-p transistor, 10¹⁰ holes enter the emitter in 10^-6 s. If 29% of holes is lost in the base, then the current amplification factor is

• 49

• 19

• 29

• 39

The electrical conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 600 nm is incident on it. The energy band gap (in eV) for the semiconductor is

• 1.50

• 0.75

• 2.06

• 1.35

The inputs A, B and C to be given in order to get an output Y = 1 from the following circuit are

• 0, 1, 0

• 1, 0, 0

• 1, 0, 1

• 1, 1, 0

45.

The collector resistance and the input resistance of a CE amplifier are respectively 10 kΩ and 2 kΩ. If β of the transistor is 49, the voltage gain of the amplifier is

• 125

• 150

• 245

• 200

The light emitting diode (LED) is

• a heavily doped p-n junction with no external bias

• a heavily doped p-n junction with reverse bias

• a heavily doped p-n junction with forward bias

• a lightly doped p-n junction with no external bias

Identify the mismatched pair from the following

• Zener diode : Voltage regulator

• Germanium doped with phosphorus : n-type semiconductor

• semiconductor : band gap > 3 eV

• p-n junction diode : rectifier

In a common-emitter configuration, a transistor has β = 50 and input resistance 1 kΩ. If the peak value of AC input is 0.01 V, then the peak value of collector current is

• 0.01 µA

• 500 µA

• 100 µA

• 0.5 µA

The waveforms A and B given below are given as input to a NAND gate. Then, its logic output y is

• for t₁ to t₂ ; y = 0

• for t₂ to t₃ ; y = 1

• for t₃ to t₄ ; y = 1

• for t₄ to t₅ ; y = 0

The logic gates giving output '1' for the inputs of '1' and 'O' are

• AND and OR

• OR and NOR

• NAND and NOR

• NAND and OR