Question

The electric conductivity of a semiconductor increases when electromagnetic radiation of wavelength shorter than 2480 nm is incident on it. Find the hand gap of the semiconductor. Given, 

  

 

Solution

Correct option is

0.5 eV

The band gap corresponds to the minimum energy required to push an electron from the valence band to the conduction band. 

  

               

               

               

               .

SIMILAR QUESTIONS

Q1

In case of n-p-n transistor the collector current is always less than the emitter current because :

Q2

Transistors are :

Q3

Which one of following gates can be served as a building block for any digital circuit? 

Q4

The decreasing order of band gap energy is :

Q5

In the case of constants  of a transistor :

Q6

An ac voltage of peak value of 20 V is connected in series with a silicon diode and a load resistance of . The forward resistance of the diode is  and the barrier voltage is 0.7 V. Find the peak current through diode and the peak voltage across the load. What will happen to these values if the diode is assumed to be ideal?   

Q7

A transistor is connected in common emitter (CE) configuration. The collector supply is 8 V and the voltage drop across a resistor of  in the collector circuit is 0.5 V. If the current gain factor  is 0.96, find the base current.  

Q8

The plate current Ip, in triode value is give by 

         

Where Ip is in milliampere and Vp and Vg are in volt. Calculate the value ofk and the grid cut-off voltage. Given, 

 milliampere are 

Q9

A semiconductor has an electron concentration of  and a hole concentration of . Calculate its conductivity. Given electron mobility = 0.135 m2V–1s–1; hole mobility = 0.048 m2V–1s–1.

Q10

Diamond, silicon and germanium each are characterised  by valence and conduction bands separated by energy band gaps respectively equal to . Which of the following statements is true?