*Simulator***Previous Years AIEEE/JEE Mains Questions**

Q. 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:

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**Sol.**(3) When postive cycle enters into diode it is forward bias while for negative half cycle it is reversed bias.

Q. The logic circuit shown below has the input wave forms â€˜Aâ€™ and â€˜Bâ€™ as shown. Pick out the correct output waveform.

**[AIEEE-2009]**
Q. The combination of gates shown below yields.
(1) XOR gate (2) NAND gate (3) OR gate (4) NOT gate

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**Sol.**(3) No need

Q. Truth table for system of four NAND gates as shown in figure is:

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**Sol.**(3) No need

Q. The I-V characteristic of an LED is

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**Sol.**(4) I $\alpha \frac{1}{\lambda}$ more $\lambda,$ less intensity and less energy.

Q. The forward biased diode connection is:

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**Sol.**(4) If n side is at low potential relative to P side then diode is forward bias.

Q. 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) $\alpha=\frac{\beta}{1+\beta}$

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**Sol.**(1,3) $\alpha=\frac{I_{C}}{I_{e}}, \beta=\frac{I_{C}}{I_{b}}$ $I_{e}=I_{b}+I_{c}$ $\Rightarrow \frac{I_{e}}{I_{c}}=\frac{I_{b}}{I_{c}}+1 \quad \Rightarrow \quad \frac{1}{\alpha}=\frac{1}{\beta}+1$

Q. 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

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**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

Q. 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

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**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

Q. 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

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**Sol.**(2) Factual

Q. 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) $90^{\circ}$

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**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.

Q. The reading of the ammeter for a silicon diode in the given circuit is :-

**[JEE Main-2018]**
Thanks but we need more questions. Please upload more previous year questions

It will be better, to have solutions along with the correct answer. It is time saving as one can easily figure out their mistakes.

Good!

BEST SOLUTIONS ACHHE BANAO

Thanks ðŸ˜ŠðŸ˜˜

Increase the no. Of questions please

tq

good collection of question

Very helpful these questions are

Thank you