NEET Electronic Devices — Set 4

Question 1

The output frequency of a full-wave rectifier with a 60 Hz input is:

Accepted Answer

A full-wave rectifier uses both half-cycles of the AC input, doubling the output frequency. For a 60 Hz input, the output frequency is $ 60 \times 2 = 120 \, \text{Hz} $.

Question 2

The drift current in a p-n junction is caused by:

Accepted Answer

Drift current results from the electric field in the depletion region, moving electrons from p-side to n-side and holes from n-side to p-side, opposing diffusion at equilibrium.

Question 3

In an intrinsic semiconductor at $ T > 0 \, \text{K} $, the conduction is due to:

Accepted Answer

At $ T > 0 \, \text{K} $, thermal energy excites electrons from the valence band to the conduction band, creating electron-hole pairs that contribute to conduction.

NEET Physics: Electronic Devices — Practice Set 4

Q1. The output frequency of a full-wave rectifier with a 60 Hz input is:

Q2. The drift current in a p-n junction is caused by:

Q3. In an intrinsic semiconductor at \( T > 0 \, \text{K} \), the conduction is due to:

Q4. A Ge crystal with \( 4 \times 10^{28} \, \text{atoms} \, \text{m}^{-3} \) is doped with 1.5 ppm of trivalent impurity. The number of holes per cubic meter is approximately:

Q5. The recombination process in a semiconductor:

Q6. The purpose of a centre-tap transformer in a full-wave rectifier is to:

Q7. The process of adding impurities to a pure semiconductor is called:

Q8. In forward bias, the resistance of a p-n junction diode is:

Q9. In an n-type semiconductor, the minority carriers are:

Q10. The ionization energy of donor electrons in an n-type semiconductor is: