Semiconductors - JEE Main Previous Year Questions with Solutions

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Why Semiconductors Is One of the Highest-Scoring JEE Main Physics Topics 

Semiconductor Electronics (Class 12, Chapter 14) is among the most reliably tested chapters in JEE Main Physics, contributing 3–5 questions every year since AIEEE began. The chapter offers a rare combination in competitive exam preparation: high weightage with relatively low mathematical complexity.

Unlike chapters such as Alternating Current or Electromagnetic Induction that demand multi-step numerical derivations, Semiconductors rewards students who understand the underlying principles — diode biasing, logic gate outputs, transistor configuration relationships, and device characteristics. Most questions are either direct conceptual recall or one-step application.

Students who thoroughly solve the AIEEE and JEE Main PYQs from this chapter will encounter no genuinely new question type — because NTA and AIEEE have been recycling the same conceptual templates for over 15 years, varying only the circuit diagram orientation or the specific input values.

💡 Expert Tip by eSaral Physics Faculty, IIT Kota: "Semiconductors is where disciplined students pocket 12–20 marks in JEE Main before the exam has even started. Logic gate questions alone contribute 1–2 questions in most papers. If you can fill any truth table in under 60 seconds, those are essentially guaranteed marks. Two days of focused preparation on this chapter — PYQs included — changes your JEE Main Physics score meaningfully."

  Simulator Previous Years AIEEE/JEE Mains Questions [esquestion] An p-n junction (D) shown in the figure can act as a rectifier. An alternating current source (V) is connected in the circuit. The current (I) in the resistor R can be shown by: #tag# [AIEEE-2009] #sol# (3) When postive cycle enters into diode it is forward bias while for negative half cycle it is reversed bias. [/esquestion] [esquestion] The logic circuit shown below has the input wave forms ‘A’ and ‘B’ as shown. Pick out the correct output waveform. #tag# [AIEEE-2009] #sol# (1) [/esquestion] [esquestion] The combination of gates shown below yields. (1) XOR gate (2) NAND gate (3) OR gate (4) NOT gate #tag# [AIEEE-2010] #sol# (3) No need [/esquestion] [esquestion] Truth table for system of four NAND gates as shown in figure is: #tag# [AIEEE-2012] #sol# (3) No need [/esquestion] [esquestion] The I-V characteristic of an LED is #tag# [JEE Main 2013] #sol# (4) I $\alpha \frac{1}{\lambda}$ more $\lambda,$ less intensity and less energy. [/esquestion] [esquestion] The forward biased diode connection is: #tag# [JEE Main-2014] #sol# (4) If n side is at low potential relative to P side then diode is forward bias. [/esquestion] [esquestion] For a common emitter configuration, if $\alpha$ and $\beta$ have their usual meanings, the incorrect relationship between $\alpha$ and $\beta$ is $(1) \alpha=\frac{\beta^{2}}{1+\beta^{2}}$ (2) $\frac{1}{\alpha}=\frac{1}{\beta}+1$ (3) $\alpha=\frac{\beta}{1-\beta}$ (4) $\alpha=\frac{\beta}{1+\beta}$ #tag# [JEE Main-2016] #sol# (1,3) $\alpha=\frac{I_{C}}{I_{e}}, \beta=\frac{I_{C}}{I_{b}}$ $I_{e}=I_{b}+I_{c}$ $\Rightarrow \frac{I_{e}}{I_{c}}=\frac{I_{b}}{I_{c}}+1 \quad \Rightarrow \quad \frac{1}{\alpha}=\frac{1}{\beta}+1$ [/esquestion] [esquestion] If a, b, c, d are inputs to a gate and x is its output, then as per the following time graph, the gate is #tag# [JEE Main-2016] #sol# (4) Output of OR gate is 0 when all inputs are 0 & output is 1 when atleast one of the input is 1. Observing output x :- It is 0 when all inputs are 0 & it is 1 when atleast one of the inputs is 1. $\therefore$ OR gate [/esquestion] [esquestion] The temperature dependence of resistances of Cu and undoped Si in the temperature range 300-400K, is best described by :- (1) Linear decrease for Cu, linear decrease for Si. (2) Linear increase for Cu, linear increase for Si. (3) Linear increase for Cu, exponential increase for Si (4) Linear increase for Cu, exponential decrease for Si #tag# [JEE Main-2016] #sol# (4) Factual Cu is conductor so with increase in temperature, resistance will increase Si is semiconductor so with increase in temperature resistance will decrease [/esquestion] [esquestion] Identify the semiconductor devices whose characteristics are given below, in the order (a), (b), (c), (d) :- (1) Zener diode, Solar cell, Simple diode, Light dependent resistance (2) Simple diode, Zener diode, Solar cell, Light dependent resistance (3) Zener diode, Simple diode, Light dependent resistance, Solar cell (4) Solar cell, Light dependent resistance, Zener diode, Simple diode #tag# [JEE Main-2016] #sol# (2) Factual [/esquestion] [esquestion] In a common emitter amplifier circuit using an n-p-n transistor, the phase difference between the input and the output voltages will be : (1) $135^{\circ}$ (2) $180^{\circ}$ (3) $45^{\circ}$ (4) $90^{\circ}$ #tag# [JEE Main-2017] #sol# (2) In common emitter amplifier circuit input and out put voltage are out of phase. When input voltage is increased then $\mathrm{i}_{\mathrm{b}}$ is increased, i also increases so voltage drop across $\mathrm{R}_{\mathrm{c}}$ is increased. However increase in voltage across $\mathrm{R}_{\mathrm{C}}$ is in opposite sense. [/esquestion] [esquestion] The reading of the ammeter for a silicon diode in the given circuit is :- #tag# [JEE Main-2018] #sol# (2) [/esquestion]

Use the JEE Mains PYQ chapter wise index to track Semiconductors alongside the other Physics chapters during revision.

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