Topic-1 Electronic devices
Electronic devices is a very important chapter since it is the base of today's technology . Marks wise also it's a very important chapter . If we check out in the last three years papers questions appeared from this chapter . The questions are as follows.
Jee mains 2016 paper questions:-
ANS(3) Linear increase for cu , exponential decrease for si .
Intrinsic semi conductor
- Thus when temperature goes up, resistance goes up. For some materials, resistivity is a linear function of temperature . The resistivity of a conductor increases with temperature . In the case of copper, the relationship between resistivity and temperature is approximately linear over a wide range of temperatures.
- So its conductivity increases. But in metal, it decreases due to the decrease in mobility. Conductivity of metal decrease with increase in temperature. For intrinsic semiconductor , conductivity increases with increase in temperature.
a b c d x(output)
0 0 0 0 0
0 0 0 1 1
0 0 1 0 1
0 0 1 1 1
0 1 0 0 1
0 1 0 1 1
1 0 1 0 1
1 0 1 1 1
- By observing the table when at least one input is high (logic one) the output is high (logic one) so the gate is OR .
ANS(2) and (4)
- By cross multiplying the below equations you can get the above relations
Jee mains 2014 paper questions:-
- Higher voltage should be connected to the anode of the diode and lower voltage should be connected to the cathode of the diode .