NEET Electronic Devices — Set 2

Question 1

In a full-wave rectifier with a capacitor filter, the output voltage is closer to:

Accepted Answer

The capacitor charges to the peak voltage of the rectified output and discharges slowly, making the output voltage nearer to the peak value of the AC input.

Question 2

Which of the following is NOT a characteristic of semiconductors?

Accepted Answer

Semiconductors have intermediate resistivity ($ 10^{-5} $ to $ 10^6 \, \Omega \, \text{m} $), covalent bonding (e.g., Si, Ge), and conductivity that increases with temperature. High conductivity ($ 10^2 $ to $ 10^8 \, \text{S} \, \text{m}^{-1} $) is typical of metals, not semiconductors.

Question 3

The time constant of a capacitor filter in a rectifier depends on:

Accepted Answer

The time constant ($ \tau = R_L C $) in a capacitor filter determines the discharge rate, depending inversely on the product of capacitance ($ C $) and load resistance ($ R_L $).

NEET Physics: Electronic Devices — Practice Set 2

Q1. In a full-wave rectifier with a capacitor filter, the output voltage is closer to:

Q2. Which of the following is NOT a characteristic of semiconductors?

Q3. The time constant of a capacitor filter in a rectifier depends on:

Q4. The diode in a rectifier circuit must have a reverse breakdown voltage:

Q5. The primary function of a p-n junction diode is to:

Q6. Why is carbon an insulator while silicon and germanium are semiconductors?

Q7. In a reverse-biased p-n junction, the dominant current is due to:

Q8. A pure Ge crystal has \( 4 \times 10^{28} \, \text{atoms} \, \text{m}^{-3} \) and is doped with 2 ppm of trivalent impurity. The number of acceptor atoms per cubic meter is:

Q9. The charge of an acceptor atom in a p-type semiconductor is effectively:

Q10. The resistivity of insulators is typically in the range: