When Ge crystals are doped with phosphorus atom, then it becomes


Correct option is

An n-type semiconductor

Phosphorus is a pentavalent atom. When a pentavalent impurity is added to a semiconductor, we obtain an n-type semiconductor.   



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? 


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


An oscillator is nothing but an amplifier with


The transfer ratio  of a transistor is 50. The input resistance of the when used in the common emitter configuration is . The peak value of the collector ac current for an ac input voltage for 0.01 V peak is