List of top Physics Questions on Semiconductors asked in UP Board XII


What is the need of doping of intrinsic semiconductors? Ideal diodes are used in the given circuits. Find the value of current in both the circuits.
On increasing temperature of a semiconductor, what will be effect on its conductivity?
Draw a circuit diagram of a p-n junction diode in reverse-biased condition and show a graph between the variation of current and voltage related with it. What is meant by avalanche breakdown?
OR
What is the difference between p-type and n-type semiconductors? A silicon diode and a load resistance of 500 Ω are joined in series with an alternating voltage source of 20 V. The forward resistance of the diode is 10 Ω and the barrier voltage is 0.7 V. Find out: (i) the peak current through the diode (ii) the peak voltage across the load.
Explain the difference between conductors and semiconductors on the basis of energy bands in solids.
What are the charge carriers in p-type of semiconductors?
How can p-type and n-type crystal from pure semiconductor be formed? Find the maximum wavelength of electromagnetic radiation which can create a hole-electron pair in germanium of a band-gap 0.65 eV.
OR
How is the conductivity of a metal and semiconductor changed with raising temperature? Calculate the conductivity of an n-type semiconductor from the following data: Density of conduction electrons = 8×1013 /cm3, Density of holes = 5×1012 /cm3, Mobility of conduction electrons = 2.3×104 cm2/V·s, Mobility of holes = 100 cm2/V·s.
Discuss the working method of a half-wave rectifier using a p-n junction diode.
How is the p-n junction diode used as a full wave rectifier? Explain its working process by making its simple circuit.
OR
What are de Broglie's matter-waves? The work function of potassium is \( 2\!\cdot\!0\ \text{eV} \). When ultraviolet light of wavelength \( 3500\ \text{\AA} \) falls on the surface of potassium, calculate the maximum kinetic energy of the emitted photoelectrons in electron-volt.
Explain the energy bands in solids.
In a semiconductor, the energy gap between the valence band and the conduction band is nearly:
Explain full wave rectifying action of p-n junction diode with the help of circuit diagram.
OR
Draw the diffraction pattern of light due to single slit and write the expression for position of minima. On what factors does the width of central maxima depend?
Draw a graph between voltage and current of a p-n junction diode in forward bias.
In the depletion layer of a p-n junction diode, there are:
Explain the difference between conductor, insulator and semiconductor on the basis of energy band in solids.
OR
Define diamagnetic, paramagnetic and ferromagnetic materials. Explain that a current carrying solenoid behaves as a bar magnet.
Explain the effect of biasing on the depletion region of a p-n junction. Using a p-n junction diode, draw the circuit diagram of a half-wave rectifier and show the shape of the input and output voltage.