Question 1

Q1: 14.1 In an n-type silicon, which of the following statement is true: (a) Electrons are majority carriers and trivalent atoms are the dopants. (b) Elec...

Accepted Answer

The correct statement is (c) Holes are minority carriers and pentavalent atoms are the dopants. Explanation:    An n-type semiconductor is created by doping a pure semiconductor like silicon (which is tetravalent) with a pentavalent impurity (valency 5), such as Arsenic (As) or Phosphorous (P). Thes...

Question 2

Q2: 14.2 Which of the statements given in Exercise 14.1 is true for p-type semiconductos.

Accepted Answer

For p-type semiconductors, the true statement is (d) Holes are majority carriers and trivalent atoms are the dopants. Explanation:    A p-type semiconductor is formed by doping a pure semiconductor like silicon with a trivalent impurity (valency 3), such as Boron (B) or Aluminium (Al). These impurit...

Question 3

Q3: 14.3 Carbon, silicon and germanium have four valence electrons each. These are characterised by valence and conduction bands separated by energy band...

Accepted Answer

The correct statement is (c) (E_g)_C > (E_g)_Si > (E_g)_Ge Explanation: Based on the text, the energy gap (E_g) between the conduction and valence bands determines whether a material is an insulator, semiconductor, or conductor. The values for Carbon, Silicon, and Germanium are given as:    For Carb...

Question 4

Q4: 14.4 In an unbiased p-n junction, holes diffuse from the p-region to n-region because (a) free electrons in the n-region attract them. (b) they move a...

Accepted Answer

The correct statement is (c) hole concentration in p-region is more as compared to n-region. Explanation: During the formation of a p-n junction, two processes occur: diffusion and drift. The initial movement of charge carriers is due to diffusion.    In a p-type semiconductor (p-region), the concen...

Question 5

Q5: 14.5 When a forward bias is applied to a p-n junction, it (a) raises the potential barrier. (b) reduces the majority carrier current to zero. (c) lowe...

Accepted Answer

The correct statement is (c) lowers the potential barrier. Explanation:    A p-n junction is forward biased when the p-side is connected to the positive terminal of a battery and the n-side is connected to the negative terminal.    The direction of this applied external voltage is opposite to the di...

Question 6

Q6: 14.6 In half-wave rectification, what is the output frequency if the input frequency is 50 Hz. What is the output frequency of a full-wave rectifier f...

Accepted Answer

For an input frequency of 50 Hz:    Half-wave rectifier: The output frequency is 50 Hz.     Explanation: A half-wave rectifier allows current to flow only during one half of the input AC cycle (either the positive or negative half). It blocks the other half. Therefore, the output waveform consists o...

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