NCERT Solutions For Chapter 14: Semiconductor Electronics

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NCERT Solutions for Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits are provided in the article below. A semiconductor is a material whose resistivity is between a conductor such as metallic copper and an insulator such as glass. Its resistivity falls as the temperature rises which is completely opposite to any metal. 

Class 12 Physics Chapter 14 Semiconductor Electronics belong to Unit 9 - Electronic Devices which has a weightage of 7 marks in the CBSE Board examinations. Class 12 Physics Semiconductor Electronics NCERT Solutions covers the concepts of intrinsic and extrinsic semiconductors, P-n Junction, and Rectifiers

Download PDF: NCERT Solutions for Class 12 Physics Chapter 14

NCERT Solutions for Class 12 Physics Chapter 14

NCERT Solutions For Class 12 Physics: Chapter 14 Semiconductor Electronics: Materials, Devices and Simple CircuitsNCERT Solutions For Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple CircuitsNCERT Solutions For Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple CircuitsNCERT Solutions For Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple CircuitsNCERT Solutions For Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple CircuitsNCERT Solutions For Class 12 Physics Chapter 14 Semiconductor Electronics: Materials, Devices and Simple Circuits

Class 12 Physics Chapter 14 – Topics Covered

  • Semiconductors have resistivity or conductivity in between that of metals and insulators.
ρ ~ 10-5. 106 Ωm, σ ~ 10+5 .10-6 Sm-1
  • Types of Semiconductors: There are two types of semiconductors – Elements Semiconductors and Compound Semiconductors.
(i) Elements Semiconductors are available in natural form, e.g. germanium and silicon.
(ii) Compound Semiconductors are made by compounding the metals, e.g. InP, CdS, polyaniline, GaAs, CdSe, anthracene, etc.
  • On the basis of purity, semiconductors are classified as intrinsic semiconductors and extrinsic semiconductors.
    Intrinsic Semiconductors are pure semiconductor that does not have any significant dopant species present

ne  = nh = ni 

where, ne and nh are the number densities of electrons and holes respectively and ni is the intrinsic carrier concentration.

  • Extrinsic Semiconductors are pure semiconductors that are doped with an impurity.
Extrinsic semiconductors are classified into two types: p-type semiconductors and n-type semiconductors.
  • Formation of Depletion Region in p-n junction: During the formation of a p-n junction, due to the concentration gradient across the p and n sides, the holes diffuse from the p-side to the n-side and electrons diffuse from the n-side to the p-side.

Formation of Depletion Region in p-n junction

Formation of Depletion Region in p-n junction


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CBSE CLASS XII Related Questions

  • 1.
    This ‘average velocity’ is found be few mm/s for currents in range of a few amperes. How then is current established almost the instant a circuit is closed ?


      • 2.
        Capacitors are manufactured with certain standard capacitances and working voltages. However, these standard values may not be the ones that are actually needed in a particular application. Two or more capacitors can be grouped in series or in parallel to achieve desired capacitance and voltage. When connected in series, the total capacitance decreases while the voltage rating increases, whereas in parallel connections, the total capacitance increases and maintains the same voltage rating. A capacitor stores energy in the electric field between its plates and stored energy is proportional to the square of the voltage and capacitance $U = \frac{1}{2}CV^2$, where symbols have their usual meanings.
        Two capacitors, one of $3 \ \mu$F and the other of $6 \ \mu$F, are connected in series in the circuit as shown in the figure, for a long time. }


          • 3.
            An electric field $\vec{E}$ is established across the ends of a cylindrical conductor of length L and area of cross-section A. Discuss how electrons attain an average velocity, independent of time. Hence, obtain a relation between current in the conductor and this ‘average velocity’ of electrons.


              • 4.
                Read the following paragraph and answer the questions that follow.
                In an experiment with convex lens of focal length f, the screen is fixed at a distance D from the object. A student slowly moves the lens away from the object towards the screen and finds that she is able to form sharp image of the object for two positions of the lens. The distance between these two positions of the lens is d.


                  • 5.
                    Read the following paragraph and answer the questions that follow.
                    A p-type or n-type semiconductor can be converted into a p-n junction by doping it with suitable impurity. The motion of majority charge carriers causes diffusion current across the junction while the barrier electric field causes motion of minority carriers for drift current. In case of unbiased diode, the diffusion and drift currents are equal. This equilibrium is disturbed by the biasing batteries. Diodes, therefore, allow currents in one direction. This property of diode is used in making rectifiers.


                      • 6.
                        The resistance of a metal wire at \( 20^\circ \text{C} \) is \( 1.05 \, \Omega \) and at \( 100^\circ \text{C} \) is \( 1.38 \, \Omega \). Determine the temperature coefficient of resistivity of this metal.

                          CBSE CLASS XII Previous Year Papers

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