In the depletion region of an unbiased pn junction diode, there are


Correct option is

Only fixed ions

As a result of electron-hole recombination, the electrons in the n-region in the vicinity of the junction are neutralized by holes so that this small region is depleted of free charge carriers (electron are neutralized by holes) and has only immobile ions.



The electrical conductivity of  a semiconductor inceases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. Find the band gap for the semiconductor. Given :



At absolute zero of temperature, the electrical conductivity of a pure semiconductor is


In pure silicon at 300 K the electron and hole concentration is each equal to . When doped with indium, the hole concentration increases to . What is the electron concentration in doped silicon?


In a transistor circuit, the collector current is 50 mA and the base current is 1 mA. The current gain  is


In a transistor circuit, the collector current is 9.8 mA and the base current is 10 mA. The current gain  is 


In a transistor amplifier, the two ac current gains  as defined as . The relation between  is


In a transistor, a change of 8.0 mA in the emitter current produces a change of 7.8 mA in the collector current. What change in the base current is necessary to produce the same change in the collector current?


In a common emitter amplifier, the output resistance is  and the input resistance . In the peak value of the signal voltage is 10 mV and , then the peak value of the output voltage is 


The base current of a transistor is  and the collector current is 2 mA. What is the current gain for the common base configuration? 


An oscillator is nothing but an amplifier with